| .. _coding_guidelines: |
| |
| Coding Guidelines |
| ################# |
| |
| The project TSC and the Safety Committee of the project agreed to implement |
| a staged and incremental approach for complying with a set of coding rules (AKA |
| Coding Guidelines) to improve quality and consistency of the code base. Below |
| are the agreed upon stages: |
| |
| Stage I (COMPLETED) |
| Coding guideline rules are available to be followed and referenced, |
| but not enforced. Rules are not yet enforced in CI and pull-requests cannot be |
| blocked by reviewers/approvers due to violations. |
| |
| Stage II |
| Begin enforcement on a limited scope of the code base. Initially, this would be |
| the safety certification scope. For rules easily applied across codebase, we |
| should not limit compliance to initial scope. This step requires tooling, |
| CI setup and an enforcement strategy. |
| |
| Stage III |
| Revisit the coding guideline rules and based on experience from previous |
| stages, refine/iterate on selected rules. |
| |
| Stage IV |
| Expand enforcement to the wider codebase. Exceptions may be granted on some |
| areas of the codebase with a proper justification. Exception would require |
| TSC approval. |
| |
| .. note:: |
| |
| Coding guideline rules may be removed/changed at any time by filing a |
| GH issue/RFC. |
| |
| .. important:: |
| |
| **Current stage:** |
| The prerequisites for entering **Stage II** are currently being looked at: |
| The tooling is in evaluation, CI setup and `enforcement strategy |
| <https://github.com/zephyrproject-rtos/zephyr/issues/58903>`__ is being worked on. |
| |
| Main rules |
| ********** |
| |
| The coding guideline rules are based on MISRA-C 2012 and are a **subset** of MISRA-C. |
| The subset is listed in the table below with a summary of the rules, its |
| severity and the equivalent rules from other standards for reference. |
| |
| .. note:: |
| |
| For existing Zephyr maintainers and collaborators, if you are unable to |
| obtain a copy through your employer, a limited number of copies will be made |
| available through the project. If you need a copy of MISRA-C 2012, please |
| send email to safety@lists.zephyrproject.org and provide details on reason |
| why you can't obtain one through other options and expected contributions |
| once you have one. The safety committee will review all requests. |
| |
| |
| .. list-table:: Main rules |
| :header-rows: 1 |
| :widths: 12 45 15 14 12 |
| |
| * - Zephyr rule |
| - Description |
| - MISRA-C 2012 rule |
| - MISRA-C severity |
| - CERT C reference |
| |
| .. _MisraC_Dir_1_1: |
| * - 1 |
| - Any implementation-defined behaviour on which the output of the program depends shall be documented and understood |
| - `Dir 1.1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/D_01_01.c>`_ |
| - Required |
| - `MSC09-C <https://wiki.sei.cmu.edu/confluence/display/c/MSC09-C.+Character+encoding%3A+Use+subset+of+ASCII+for+safety>`_ |
| |
| .. _MisraC_Dir_2_1: |
| * - 2 |
| - All source files shall compile without any compilation errors |
| - `Dir 2.1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/D_02_01.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Dir_3_1: |
| * - 3 |
| - All code shall be traceable to documented requirements |
| - `Dir 3.1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/D_03_01.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Dir_4_1: |
| * - 4 |
| - Run-time failures shall be minimized |
| - `Dir 4.1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/D_04_01.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Dir_4_2: |
| * - 5 |
| - All usage of assembly language should be documented |
| - `Dir 4.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/D_04_02.c>`_ |
| - Advisory |
| - N/A |
| |
| .. _MisraC_Dir_4_4: |
| * - 6 |
| - Sections of code should not be “commented out” |
| - `Dir 4.4 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/D_04_04.c>`_ |
| - Advisory |
| - `MSC04-C <https://wiki.sei.cmu.edu/confluence/display/c/MSC04-C.+Use+comments+consistently+and+in+a+readable+fashion>`_ |
| |
| .. _MisraC_Dir_4_5: |
| * - 7 |
| - Identifiers in the same name space with overlapping visibility should be typographically unambiguous |
| - `Dir 4.5 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/D_04_05.c>`_ |
| - Advisory |
| - `DCL02-C <https://wiki.sei.cmu.edu/confluence/display/c/DCL02-C.+Use+visually+distinct+identifiers>`_ |
| |
| .. _MisraC_Dir_4_6: |
| * - 8 |
| - typedefs that indicate size and signedness should be used in place of the basic numerical types |
| - `Dir 4.6 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/D_04_06.c>`_ |
| - Advisory |
| - N/A |
| |
| .. _MisraC_Dir_4_7: |
| * - 9 |
| - If a function returns error information, then that error information shall be tested |
| - `Dir 4.7 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/D_04_07.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Dir_4_8: |
| * - 10 |
| - If a pointer to a structure or union is never dereferenced within a translation unit, then the implementation of the object should be hidden |
| - | `Dir 4.8 example 1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/D_04_08_1.c>`_ |
| | `Dir 4.8 example 2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/D_04_08_2.c>`_ |
| - Advisory |
| - `DCL12-C <https://wiki.sei.cmu.edu/confluence/display/c/DCL12-C.+Implement+abstract+data+types+using+opaque+types>`_ |
| |
| .. _MisraC_Dir_4_9: |
| * - 11 |
| - A function should be used in preference to a function-like macro where they are interchangeable |
| - `Dir 4.9 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/D_04_09.c>`_ |
| - Advisory |
| - `PRE00-C <https://wiki.sei.cmu.edu/confluence/display/c/PRE00-C.+Prefer+inline+or+static+functions+to+function-like+macros>`_ |
| |
| .. _MisraC_Dir_4_10: |
| * - 12 |
| - Precautions shall be taken in order to prevent the contents of a header file being included more than once |
| - `Dir 4.10 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/D_04_10.c>`_ |
| - Required |
| - `PRE06-C <https://wiki.sei.cmu.edu/confluence/display/c/PRE06-C.+Enclose+header+files+in+an+include+guard>`_ |
| |
| .. _MisraC_Dir_4_11: |
| * - 13 |
| - The validity of values passed to library functions shall be checked |
| - `Dir 4.11 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/D_04_11.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Dir_4_12: |
| * - 14 |
| - Dynamic memory allocation shall not be used |
| - `Dir 4.12 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/D_04_12.c>`_ |
| - Required |
| - `STR01-C <https://wiki.sei.cmu.edu/confluence/display/c/STR01-C.+Adopt+and+implement+a+consistent+plan+for+managing+strings>`_ |
| |
| .. _MisraC_Dir_4_13: |
| * - 15 |
| - Functions which are designed to provide operations on a resource should be called in an appropriate sequence |
| - `Dir 4.13 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/D_04_13.c>`_ |
| - Advisory |
| - N/A |
| |
| .. _MisraC_Dir_4_14: |
| * - 16 |
| - The validity of values received from external sources shall be checked |
| - `Dir 4.14 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/D_04_14.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_1_2: |
| * - 17 |
| - Language extensions should not be used |
| - `Rule 1.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_01_02.c>`_ |
| - Advisory |
| - `MSC04-C <https://wiki.sei.cmu.edu/confluence/display/c/MSC04-C.+Use+comments+consistently+and+in+a+readable+fashion>`_ |
| |
| .. _MisraC_Rule_1_3: |
| * - 18 |
| - There shall be no occurrence of undefined or critical unspecified behaviour |
| - `Rule 1.3 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_01_03.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_2_1: |
| * - 19 |
| - A project shall not contain unreachable code |
| - | `Rule 2.1 example 1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_02_01_1.c>`_ |
| | `Rule 2.1 example 2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_02_01_2.c>`_ |
| - Required |
| - `MSC07-C <https://wiki.sei.cmu.edu/confluence/display/c/MSC07-C.+Detect+and+remove+dead+code>`_ |
| |
| .. _MisraC_Rule_2_2: |
| * - 20 |
| - There shall be no dead code |
| - `Rule 2.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_02_02.c>`_ |
| - Required |
| - `MSC12-C <https://wiki.sei.cmu.edu/confluence/display/c/MSC12-C.+Detect+and+remove+code+that+has+no+effect+or+is+never+executed>`_ |
| |
| .. _MisraC_Rule_2_3: |
| * - 21 |
| - A project should not contain unused type declarations |
| - `Rule 2.3 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_02_03.c>`_ |
| - Advisory |
| - N/A |
| |
| .. _MisraC_Rule_2_6: |
| * - 22 |
| - A function should not contain unused label declarations |
| - `Rule 2.6 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_02_06.c>`_ |
| - Advisory |
| - N/A |
| |
| .. _MisraC_Rule_2_7: |
| * - 23 |
| - There should be no unused parameters in functions |
| - `Rule 2.7 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_02_07.c>`_ |
| - Advisory |
| - N/A |
| |
| .. _MisraC_Rule_3_1: |
| * - 24 |
| - The character sequences /* and // shall not be used within a comment |
| - `Rule 3.1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_03_01.c>`_ |
| - Required |
| - `MSC04-C <https://wiki.sei.cmu.edu/confluence/display/c/MSC04-C.+Use+comments+consistently+and+in+a+readable+fashion>`_ |
| |
| .. _MisraC_Rule_3_2: |
| * - 25 |
| - Line-splicing shall not be used in // comments |
| - `Rule 3.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_03_02.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_4_1: |
| * - 26 |
| - Octal and hexadecimal escape sequences shall be terminated |
| - `Rule 4.1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_04_01.c>`_ |
| - Required |
| - `MSC09-C <https://wiki.sei.cmu.edu/confluence/display/c/MSC09-C.+Character+encoding%3A+Use+subset+of+ASCII+for+safety>`_ |
| |
| .. _MisraC_Rule_4_2: |
| * - 27 |
| - Trigraphs should not be used |
| - `Rule 4.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_04_02.c>`_ |
| - Advisory |
| - `PRE07-C <https://wiki.sei.cmu.edu/confluence/display/c/PRE07-C.+Avoid+using+repeated+question+marks>`_ |
| |
| .. _MisraC_Rule_5_1: |
| * - 28 |
| - External identifiers shall be distinct |
| - | `Rule 5.1 example 1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_01_1.c>`_ |
| | `Rule 5.1 example 2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_01_2.c>`_ |
| - Required |
| - `DCL23-C <https://wiki.sei.cmu.edu/confluence/display/c/DCL23-C.+Guarantee+that+mutually+visible+identifiers+are+unique>`_ |
| |
| .. _MisraC_Rule_5_2: |
| * - 29 |
| - Identifiers declared in the same scope and name space shall be distinct |
| - `Rule 5.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_02.c>`_ |
| - Required |
| - `DCL23-C <https://wiki.sei.cmu.edu/confluence/display/c/DCL23-C.+Guarantee+that+mutually+visible+identifiers+are+unique>`_ |
| |
| .. _MisraC_Rule_5_3: |
| * - 30 |
| - An identifier declared in an inner scope shall not hide an identifier declared in an outer scope |
| - `Rule 5.3 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_03.c>`_ |
| - Required |
| - `DCL23-C <https://wiki.sei.cmu.edu/confluence/display/c/DCL23-C.+Guarantee+that+mutually+visible+identifiers+are+unique>`_ |
| |
| .. _MisraC_Rule_5_4: |
| * - 31 |
| - Macro identifiers shall be distinct |
| - `Rule 5.4 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_04.c>`_ |
| - Required |
| - `DCL23-C <https://wiki.sei.cmu.edu/confluence/display/c/DCL23-C.+Guarantee+that+mutually+visible+identifiers+are+unique>`_ |
| |
| .. _MisraC_Rule_5_5: |
| * - 32 |
| - Identifiers shall be distinct from macro names |
| - `Rule 5.5 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ |
| - Required |
| - `DCL23-C <https://wiki.sei.cmu.edu/confluence/display/c/DCL23-C.+Guarantee+that+mutually+visible+identifiers+are+unique>`_ |
| |
| .. _MisraC_Rule_5_6: |
| * - 33 |
| - A typedef name shall be a unique identifier |
| - `Rule 5.6 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_06.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_5_7: |
| * - 34 |
| - A tag name shall be a unique identifier |
| - `Rule 5.7 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_07.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_5_8: |
| * - 35 |
| - Identifiers that define objects or functions with external linkage shall be unique |
| - | `Rule 5.8 example 1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_08_1.c>`_ |
| | `Rule 5.8 example 2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_08_2.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_5_9: |
| * - 36 |
| - Identifiers that define objects or functions with internal linkage should be unique |
| - | `Rule 5.9 example 1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_09_1.c>`_ |
| | `Rule 5.9 example 2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_09_2.c>`_ |
| - Advisory |
| - N/A |
| |
| .. _MisraC_Rule_6_1: |
| * - 37 |
| - Bit-fields shall only be declared with an appropriate type |
| - `Rule 6.1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_06_01.c>`_ |
| - Required |
| - `INT14-C <https://wiki.sei.cmu.edu/confluence/display/c/INT14-C.+Avoid+performing+bitwise+and+arithmetic+operations+on+the+same+data>`_ |
| |
| .. _MisraC_Rule_6_2: |
| * - 38 |
| - Single-bit named bit fields shall not be of a signed type |
| - `Rule 6.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_06_02.c>`_ |
| - Required |
| - `INT14-C <https://wiki.sei.cmu.edu/confluence/display/c/INT14-C.+Avoid+performing+bitwise+and+arithmetic+operations+on+the+same+data>`_ |
| |
| .. _MisraC_Rule_7_1: |
| * - 39 |
| - Octal constants shall not be used |
| - `Rule 7.1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_07_01.c>`_ |
| - Required |
| - `DCL18-C <https://wiki.sei.cmu.edu/confluence/display/c/DCL18-C.+Do+not+begin+integer+constants+with+0+when+specifying+a+decimal+value>`_ |
| |
| .. _MisraC_Rule_7_2: |
| * - 40 |
| - A u or U suffix shall be applied to all integer constants that are represented in an unsigned type |
| - `Rule 7.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_07_02.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_7_3: |
| * - 41 |
| - The lowercase character l shall not be used in a literal suffix |
| - `Rule 7.3 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_07_03.c>`_ |
| - Required |
| - `DCL16-C <https://wiki.sei.cmu.edu/confluence/pages/viewpage.action?pageId=87152241>`_ |
| |
| .. _MisraC_Rule_7_4: |
| * - 42 |
| - A string literal shall not be assigned to an object unless the objects type is pointer to const-qualified char |
| - `Rule 7.4 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_07_04.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_8_1: |
| * - 43 |
| - Types shall be explicitly specified |
| - `Rule 8.1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_08_01.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_8_2: |
| * - 44 |
| - Function types shall be in prototype form with named parameters |
| - `Rule 8.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_08_02.c>`_ |
| - Required |
| - `DCL20-C <https://wiki.sei.cmu.edu/confluence/display/c/DCL20-C.+Explicitly+specify+void+when+a+function+accepts+no+arguments>`_ |
| |
| .. _MisraC_Rule_8_3: |
| * - 45 |
| - All declarations of an object or function shall use the same names and type qualifiers |
| - `Rule 8.3 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_08_03.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_8_4: |
| * - 46 |
| - A compatible declaration shall be visible when an object or function with external linkage is defined |
| - `Rule 8.4 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_08_04.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_8_5: |
| * - 47 |
| - An external object or function shall be declared once in one and only one file |
| - | `Rule 8.5 example 1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_08_05_1.c>`_ |
| | `Rule 8.5 example 2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_08_05_2.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_8_6: |
| * - 48 |
| - An identifier with external linkage shall have exactly one external definition |
| - | `Rule 8.6 example 1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_08_06_1.c>`_ |
| | `Rule 8.6 example 2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_08_06_2.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_8_8: |
| * - 49 |
| - The static storage class specifier shall be used in all declarations of objects and functions that have internal linkage |
| - `Rule 8.8 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_08_08.c>`_ |
| - Required |
| - `DCL15-C <https://wiki.sei.cmu.edu/confluence/display/c/DCL15-C.+Declare+file-scope+objects+or+functions+that+do+not+need+external+linkage+as+static>`_ |
| |
| .. _MisraC_Rule_8_9: |
| * - 50 |
| - An object should be defined at block scope if its identifier only appears in a single function |
| - `Rule 8.9 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_08_09.c>`_ |
| - Advisory |
| - `DCL19-C <https://wiki.sei.cmu.edu/confluence/display/c/DCL19-C.+Minimize+the+scope+of+variables+and+functions>`_ |
| |
| .. _MisraC_Rule_8_10: |
| * - 51 |
| - An inline function shall be declared with the static storage class |
| - `Rule 8.10 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_08_10.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_8_12: |
| * - 52 |
| - Within an enumerator list, the value of an implicitly-specified enumeration constant shall be unique |
| - `Rule 8.12 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_08_12.c>`_ |
| - Required |
| - `INT09-C <https://wiki.sei.cmu.edu/confluence/display/c/INT09-C.+Ensure+enumeration+constants+map+to+unique+values>`_ |
| |
| .. _MisraC_Rule_8_14: |
| * - 53 |
| - The restrict type qualifier shall not be used |
| - `Rule 8.14 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_08_14.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_9_1: |
| * - 54 |
| - The value of an object with automatic storage duration shall not be read before it has been set |
| - `Rule 9.1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_09_01.c>`_ |
| - Mandatory |
| - N/A |
| |
| .. _MisraC_Rule_9_2: |
| * - 55 |
| - The initializer for an aggregate or union shall be enclosed in braces |
| - `Rule 9.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_09_02.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_9_3: |
| * - 56 |
| - Arrays shall not be partially initialized |
| - `Rule 9.3 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_09_03.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_9_4: |
| * - 57 |
| - An element of an object shall not be initialized more than once |
| - `Rule 9.4 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_09_04.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_9_5: |
| * - 58 |
| - Where designated initializers are used to initialize an array object the size of the array shall be specified explicitly |
| - `Rule 9.5 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_09_05.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_10_1: |
| * - 59 |
| - Operands shall not be of an inappropriate essential type |
| - `Rule 10.1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_10_01.c>`_ |
| - Required |
| - `STR04-C <https://wiki.sei.cmu.edu/confluence/display/c/STR04-C.+Use+plain+char+for+characters+in+the+basic+character+set>`_ |
| |
| .. _MisraC_Rule_10_2: |
| * - 60 |
| - Expressions of essentially character type shall not be used inappropriately in addition and subtraction operations |
| - `Rule 10.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_10_02.c>`_ |
| - Required |
| - `STR04-C <https://wiki.sei.cmu.edu/confluence/display/c/STR04-C.+Use+plain+char+for+characters+in+the+basic+character+set>`_ |
| |
| .. _MisraC_Rule_10_3: |
| * - 61 |
| - The value of an expression shall not be assigned to an object with a narrower essential type or of a different essential type category |
| - `Rule 10.3 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_10_03.c>`_ |
| - Required |
| - `STR04-C <https://wiki.sei.cmu.edu/confluence/display/c/STR04-C.+Use+plain+char+for+characters+in+the+basic+character+set>`_ |
| |
| .. _MisraC_Rule_10_4: |
| * - 62 |
| - Both operands of an operator in which the usual arithmetic conversions are performed shall have the same essential type category |
| - `Rule 10.4 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_10_04.c>`_ |
| - Required |
| - `STR04-C <https://wiki.sei.cmu.edu/confluence/display/c/STR04-C.+Use+plain+char+for+characters+in+the+basic+character+set>`_ |
| |
| .. _MisraC_Rule_10_5: |
| * - 63 |
| - The value of an expression should not be cast to an inappropriate essential type |
| - `Rule 10.5 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_10_05.c>`_ |
| - Advisory |
| - N/A |
| |
| .. _MisraC_Rule_10_6: |
| * - 64 |
| - The value of a composite expression shall not be assigned to an object with wider essential type |
| - `Rule 10.6 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_10_06.c>`_ |
| - Required |
| - `INT02-C <https://wiki.sei.cmu.edu/confluence/display/c/INT02-C.+Understand+integer+conversion+rules>`_ |
| |
| .. _MisraC_Rule_10_7: |
| * - 65 |
| - If a composite expression is used as one operand of an operator in which the usual arithmetic conversions are performed then the other operand shall not have wider essential type |
| - `Rule 10.7 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_10_07.c>`_ |
| - Required |
| - `INT02-C <https://wiki.sei.cmu.edu/confluence/display/c/INT02-C.+Understand+integer+conversion+rules>`_ |
| |
| .. _MisraC_Rule_10_8: |
| * - 66 |
| - The value of a composite expression shall not be cast to a different essential type category or a wider essential type |
| - `Rule 10.8 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_10_08.c>`_ |
| - Required |
| - `INT02-C <https://wiki.sei.cmu.edu/confluence/display/c/INT02-C.+Understand+integer+conversion+rules>`_ |
| |
| .. _MisraC_Rule_11_2: |
| * - 67 |
| - Conversions shall not be performed between a pointer to an incomplete type and any other type |
| - `Rule 11.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_11_02.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_11_6: |
| * - 68 |
| - A cast shall not be performed between pointer to void and an arithmetic type |
| - `Rule 11.6 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_11_06.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_11_7: |
| * - 69 |
| - A cast shall not be performed between pointer to object and a noninteger arithmetic type |
| - `Rule 11.7 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_11_07.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_11_8: |
| * - 70 |
| - A cast shall not remove any const or volatile qualification from the type pointed to by a pointer |
| - `Rule 11.8 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_11_08.c>`_ |
| - Required |
| - `EXP05-C <https://wiki.sei.cmu.edu/confluence/display/c/EXP05-C.+Do+not+cast+away+a+const+qualification>`_ |
| |
| .. _MisraC_Rule_11_9: |
| * - 71 |
| - The macro NULL shall be the only permitted form of integer null pointer constant |
| - `Rule 11.9 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_11_09.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_12_1: |
| * - 72 |
| - The precedence of operators within expressions should be made explicit |
| - `Rule 12.1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_12_01.c>`_ |
| - Advisory |
| - `EXP00-C <https://wiki.sei.cmu.edu/confluence/display/c/EXP00-C.+Use+parentheses+for+precedence+of+operation>`_ |
| |
| .. _MisraC_Rule_12_2: |
| * - 73 |
| - The right hand operand of a shift operator shall lie in the range zero to one less than the width in bits of the essential type of the left hand operand |
| - `Rule 12.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_12_02.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_12_4: |
| * - 74 |
| - Evaluation of constant expressions should not lead to unsigned integer wrap-around |
| - `Rule 12.4 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_12_04.c>`_ |
| - Advisory |
| - N/A |
| |
| .. _MisraC_Rule_12_5: |
| * - 75 |
| - The sizeof operator shall not have an operand which is a function parameter declared as “array of type” |
| - `Rule 12.5 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_12_05.c>`_ |
| - Mandatory |
| - N/A |
| |
| .. _MisraC_Rule_13_1: |
| * - 76 |
| - Initializer lists shall not contain persistent side effects |
| - | `Rule 13.1 example 1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_13_01_1.c>`_ |
| | `Rule 13.1 example 2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_13_01_2.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_13_2: |
| * - 77 |
| - The value of an expression and its persistent side effects shall be the same under all permitted evaluation orders |
| - `Rule 13.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_13_02.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_13_3: |
| * - 78 |
| - A full expression containing an increment (++) or decrement (--) operator should have no other potential side effects other than that caused by the increment or decrement operator |
| - `Rule 13.3 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_13_03.c>`_ |
| - Advisory |
| - N/A |
| |
| .. _MisraC_Rule_13_4: |
| * - 79 |
| - The result of an assignment operator should not be used |
| - `Rule 13.4 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_13_04.c>`_ |
| - Advisory |
| - N/A |
| |
| .. _MisraC_Rule_13_5: |
| * - 80 |
| - The right hand operand of a logical && or || operator shall not contain persistent side effects |
| - | `Rule 13.5 example 1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_13_05_1.c>`_ |
| | `Rule 13.5 example 2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_13_05_2.c>`_ |
| - Required |
| - `EXP10-C <https://wiki.sei.cmu.edu/confluence/display/c/EXP10-C.+Do+not+depend+on+the+order+of+evaluation+of+subexpressions+or+the+order+in+which+side+effects+take+place>`_ |
| |
| .. _MisraC_Rule_13_6: |
| * - 81 |
| - The operand of the sizeof operator shall not contain any expression which has potential side effects |
| - `Rule 13.6 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_13_06.c>`_ |
| - Mandatory |
| - N/A |
| |
| .. _MisraC_Rule_14_1: |
| * - 82 |
| - A loop counter shall not have essentially floating type |
| - `Rule 14.1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_14_01.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_14_2: |
| * - 83 |
| - A for loop shall be well-formed |
| - `Rule 14.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_14_02.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_14_3: |
| * - 84 |
| - Controlling expressions shall not be invariant |
| - `Rule 14.3 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_14_03.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_14_4: |
| * - 85 |
| - The controlling expression of an if statement and the controlling expression of an iteration-statement shall have essentially Boolean type |
| - `Rule 14.4 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_14_04.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_15_2: |
| * - 86 |
| - The goto statement shall jump to a label declared later in the same function |
| - `Rule 15.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_15_02.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_15_3: |
| * - 87 |
| - Any label referenced by a goto statement shall be declared in the same block, or in any block enclosing the goto statement |
| - `Rule 15.3 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_15_03.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_15_6: |
| * - 88 |
| - The body of an iteration-statement or a selection-statement shall be a compound-statement |
| - `Rule 15.6 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_15_06.c>`_ |
| - Required |
| - `EXP19-C <https://wiki.sei.cmu.edu/confluence/display/c/EXP19-C.+Use+braces+for+the+body+of+an+if%2C+for%2C+or+while+statement>`_ |
| |
| .. _MisraC_Rule_15_7: |
| * - 89 |
| - All if else if constructs shall be terminated with an else statement |
| - `Rule 15.7 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_15_07.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_16_1: |
| * - 90 |
| - All switch statements shall be well-formed |
| - `Rule 16.1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_16_01.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_16_2: |
| * - 91 |
| - A switch label shall only be used when the most closely-enclosing compound statement is the body of a switch statement |
| - `Rule 16.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_16_02.c>`_ |
| - Required |
| - `MSC20-C <https://wiki.sei.cmu.edu/confluence/display/c/MSC20-C.+Do+not+use+a+switch+statement+to+transfer+control+into+a+complex+block>`_ |
| |
| .. _MisraC_Rule_16_3: |
| * - 92 |
| - An unconditional break statement shall terminate every switch-clause |
| - `Rule 16.3 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_16_03.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_16_4: |
| * - 93 |
| - Every switch statement shall have a default label |
| - `Rule 16.4 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_16_04.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_16_5: |
| * - 94 |
| - A default label shall appear as either the first or the last switch label of a switch statement |
| - `Rule 16.5 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_16_05.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_16_6: |
| * - 95 |
| - Every switch statement shall have at least two switch-clauses |
| - `Rule 16.6 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_16_06.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_16_7: |
| * - 96 |
| - A switch-expression shall not have essentially Boolean type |
| - `Rule 16.7 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_16_07.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_17_1: |
| * - 97 |
| - The features of <stdarg.h> shall not be used |
| - `Rule 17.1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_17_01.c>`_ |
| - Required |
| - `ERR00-C <https://wiki.sei.cmu.edu/confluence/display/c/ERR00-C.+Adopt+and+implement+a+consistent+and+comprehensive+error-handling+policy>`_ |
| |
| .. _MisraC_Rule_17_2: |
| * - 98 |
| - Functions shall not call themselves, either directly or indirectly |
| - `Rule 17.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_17_02.c>`_ |
| - Required |
| - `MEM05-C <https://wiki.sei.cmu.edu/confluence/display/c/MEM05-C.+Avoid+large+stack+allocations>`_ |
| |
| .. _MisraC_Rule_17_3: |
| * - 99 |
| - A function shall not be declared implicitly |
| - `Rule 17.3 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_17_03.c>`_ |
| - Mandatory |
| - N/A |
| |
| .. _MisraC_Rule_17_4: |
| * - 100 |
| - All exit paths from a function with non-void return type shall have an explicit return statement with an expression |
| - `Rule 17.4 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_17_04.c>`_ |
| - Mandatory |
| - N/A |
| |
| .. _MisraC_Rule_17_5: |
| * - 101 |
| - The function argument corresponding to a parameter declared to have an array type shall have an appropriate number of elements |
| - `Rule 17.5 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_17_05.c>`_ |
| - Advisory |
| - N/A |
| |
| .. _MisraC_Rule_17_6: |
| * - 102 |
| - The declaration of an array parameter shall not contain the static keyword between the [ ] |
| - `Rule 17.6 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_17_06.c>`_ |
| - Mandatory |
| - N/A |
| |
| .. _MisraC_Rule_17_7: |
| * - 103 |
| - The value returned by a function having non-void return type shall be used |
| - `Rule 17.7 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_17_07.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_18_1: |
| * - 104 |
| - A pointer resulting from arithmetic on a pointer operand shall address an element of the same array as that pointer operand |
| - `Rule 18.1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_18_01.c>`_ |
| - Required |
| - `EXP08-C <https://wiki.sei.cmu.edu/confluence/display/c/EXP08-C.+Ensure+pointer+arithmetic+is+used+correctly>`_ |
| |
| .. _MisraC_Rule_18_2: |
| * - 105 |
| - Subtraction between pointers shall only be applied to pointers that address elements of the same array |
| - `Rule 18.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_18_02.c>`_ |
| - Required |
| - `EXP08-C <https://wiki.sei.cmu.edu/confluence/display/c/EXP08-C.+Ensure+pointer+arithmetic+is+used+correctly>`_ |
| |
| .. _MisraC_Rule_18_3: |
| * - 106 |
| - The relational operators >, >=, < and <= shall not be applied to objects of pointer type except where they point into the same object |
| - `Rule 18.3 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_18_03.c>`_ |
| - Required |
| - `EXP08-C <https://wiki.sei.cmu.edu/confluence/display/c/EXP08-C.+Ensure+pointer+arithmetic+is+used+correctly>`_ |
| |
| .. _MisraC_Rule_18_5: |
| * - 107 |
| - Declarations should contain no more than two levels of pointer nesting |
| - `Rule 18.5 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_18_05.c>`_ |
| - Advisory |
| - N/A |
| |
| .. _MisraC_Rule_18_6: |
| * - 108 |
| - The address of an object with automatic storage shall not be copied to another object that persists after the first object has ceased to exist |
| - | `Rule 18.6 example 1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_18_06_1.c>`_ |
| | `Rule 18.6 example 2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_18_06_2.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_18_8: |
| * - 109 |
| - Variable-length array types shall not be used |
| - `Rule 18.8 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_18_08.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_19_1: |
| * - 110 |
| - An object shall not be assigned or copied to an overlapping object |
| - `Rule 19.1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_19_01.c>`_ |
| - Mandatory |
| - N/A |
| |
| .. _MisraC_Rule_20_2: |
| * - 111 |
| - The ', or \ characters and the /* or // character sequences shall not occur in a header file name" |
| - `Rule 20.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_20_02.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_20_3: |
| * - 112 |
| - The #include directive shall be followed by either a <filename> or "filename" sequence |
| - `Rule 20.3 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_20_03.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_20_4: |
| * - 113 |
| - A macro shall not be defined with the same name as a keyword |
| - `Rule 20.4 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_20_04.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_20_7: |
| * - 114 |
| - Expressions resulting from the expansion of macro parameters shall be enclosed in parentheses |
| - `Rule 20.7 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_20_07.c>`_ |
| - Required |
| - `PRE01-C <https://wiki.sei.cmu.edu/confluence/display/c/PRE01-C.+Use+parentheses+within+macros+around+parameter+names>`_ |
| |
| .. _MisraC_Rule_20_8: |
| * - 115 |
| - The controlling expression of a #if or #elif preprocessing directive shall evaluate to 0 or 1 |
| - `Rule 20.8 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_20_08.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_20_9: |
| * - 116 |
| - All identifiers used in the controlling expression of #if or #elif preprocessing directives shall be #defined before evaluation |
| - `Rule 20.9 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_20_09.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_20_11: |
| * - 117 |
| - A macro parameter immediately following a # operator shall not immediately be followed by a ## operator |
| - `Rule 20.11 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_20_11.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_20_12: |
| * - 118 |
| - A macro parameter used as an operand to the # or ## operators, which is itself subject to further macro replacement, shall only be used as an operand to these operators |
| - `Rule 20.12 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_20_12.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_20_13: |
| * - 119 |
| - A line whose first token is # shall be a valid preprocessing directive |
| - `Rule 20.13 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_20_13.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_20_14: |
| * - 120 |
| - All #else, #elif and #endif preprocessor directives shall reside in the same file as the #if, #ifdef or #ifndef directive to which they are related |
| - `Rule 20.14 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_20_14.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_21_1: |
| * - 121 |
| - #define and #undef shall not be used on a reserved identifier or reserved macro name |
| - `Rule 21.1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_01.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_21_2: |
| * - 122 |
| - A reserved identifier or macro name shall not be declared |
| - `Rule 21.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_02.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_21_3: |
| * - 123 |
| - The memory allocation and deallocation functions of <stdlib.h> shall not be used |
| - `Rule 21.3 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_03.c>`_ |
| - Required |
| - `MSC24-C <https://wiki.sei.cmu.edu/confluence/display/c/MSC24-C.+Do+not+use+deprecated+or+obsolescent+functions>`_ |
| |
| .. _MisraC_Rule_21_4: |
| * - 124 |
| - The standard header file <setjmp.h> shall not be used |
| - `Rule 21.4 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_04.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_21_6: |
| * - 125 |
| - The Standard Library input/output functions shall not be used |
| - `Rule 21.6 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_06.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_21_7: |
| * - 126 |
| - The atof, atoi, atol and atoll functions of <stdlib.h> shall not be used |
| - `Rule 21.7 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_07.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_21_9: |
| * - 127 |
| - The library functions bsearch and qsort of <stdlib.h> shall not be used |
| - `Rule 21.9 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_09.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_21_11: |
| * - 128 |
| - The standard header file <tgmath.h> shall not be used |
| - `Rule 21.11 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_11.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_21_12: |
| * - 129 |
| - The exception handling features of <fenv.h> should not be used |
| - `Rule 21.12 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_12.c>`_ |
| - Advisory |
| - N/A |
| |
| .. _MisraC_Rule_21_13: |
| * - 130 |
| - Any value passed to a function in <ctype.h> shall be representable as an unsigned char or be the value EO |
| - `Rule 21.13 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_13.c>`_ |
| - Mandatory |
| - N/A |
| |
| .. _MisraC_Rule_21_14: |
| * - 131 |
| - The Standard Library function memcmp shall not be used to compare null terminated strings |
| - `Rule 21.14 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_14.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_21_15: |
| * - 132 |
| - The pointer arguments to the Standard Library functions memcpy, memmove and memcmp shall be pointers to qualified or unqualified versions of compatible types |
| - `Rule 21.15 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_15.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_21_16: |
| * - 133 |
| - The pointer arguments to the Standard Library function memcmp shall point to either a pointer type, an essentially signed type, an essentially unsigned type, an essentially Boolean type or an essentially enum type |
| - `Rule 21.16 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_16.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_21_17: |
| * - 134 |
| - Use of the string handling functions from <string.h> shall not result in accesses beyond the bounds of the objects referenced by their pointer parameters |
| - `Rule 21.17 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_17.c>`_ |
| - Mandatory |
| - N/A |
| |
| .. _MisraC_Rule_21_18: |
| * - 135 |
| - The size_t argument passed to any function in <string.h> shall have an appropriate value |
| - `Rule 21.18 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_18.c>`_ |
| - Mandatory |
| - N/A |
| |
| .. _MisraC_Rule_21_19: |
| * - 136 |
| - The pointers returned by the Standard Library functions localeconv, getenv, setlocale or, strerror shall only be used as if they have pointer to const-qualified type |
| - `Rule 21.19 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_19.c>`_ |
| - Mandatory |
| - N/A |
| |
| .. _MisraC_Rule_21_20: |
| * - 137 |
| - The pointer returned by the Standard Library functions asctime, ctime, gmtime, localtime, localeconv, getenv, setlocale or strerror shall not be used following a subsequent call to the same function |
| - `Rule 21.20 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_20.c>`_ |
| - Mandatory |
| - N/A |
| |
| .. _MisraC_Rule_22_1: |
| * - 138 |
| - All resources obtained dynamically by means of Standard Library functions shall be explicitly released |
| - `Rule 22.1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_22_01.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_22_2: |
| * - 139 |
| - A block of memory shall only be freed if it was allocated by means of a Standard Library function |
| - `Rule 22.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_22_02.c>`_ |
| - Mandatory |
| - N/A |
| |
| .. _MisraC_Rule_22_3: |
| * - 140 |
| - The same file shall not be open for read and write access at the same time on different streams |
| - `Rule 22.3 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_22_03.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_22_4: |
| * - 141 |
| - There shall be no attempt to write to a stream which has been opened as read-only |
| - `Rule 22.4 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_22_04.c>`_ |
| - Mandatory |
| - N/A |
| |
| .. _MisraC_Rule_22_5: |
| * - 142 |
| - A pointer to a FILE object shall not be dereferenced |
| - `Rule 22.5 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_22_05.c>`_ |
| - Mandatory |
| - N/A |
| |
| .. _MisraC_Rule_22_6: |
| * - 143 |
| - The value of a pointer to a FILE shall not be used after the associated stream has been closed |
| - `Rule 22.6 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_22_06.c>`_ |
| - Mandatory |
| - N/A |
| |
| .. _MisraC_Rule_22_7: |
| * - 144 |
| - The macro EOF shall only be compared with the unmodified return value from any Standard Library function capable of returning EOF |
| - `Rule 22.7 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_22_07.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_22_8: |
| * - 145 |
| - The value of errno shall be set to zero prior to a call to an errno-setting-function |
| - `Rule 22.8 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_22_08.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_22_9: |
| * - 146 |
| - The value of errno shall be tested against zero after calling an errno-setting-function |
| - `Rule 22.9 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_22_09.c>`_ |
| - Required |
| - N/A |
| |
| .. _MisraC_Rule_22_10: |
| * - 147 |
| - The value of errno shall only be tested when the last function to be called was an errno-setting-function |
| - `Rule 22.10 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_22_10.c>`_ |
| - Required |
| - N/A |
| |
| Additional rules |
| **************** |
| |
| Rule A.1: Conditional Compilation |
| ================================= |
| |
| Severity |
| -------- |
| |
| Required |
| |
| Description |
| ----------- |
| |
| Do not conditionally compile function declarations in header files. Do not |
| conditionally compile structure declarations in header files. You may |
| conditionally exclude fields within structure definitions to avoid wasting |
| memory when the feature they support is not enabled. |
| |
| Rationale |
| --------- |
| |
| Excluding declarations from the header based on compile-time options may prevent |
| their documentation from being generated. Their absence also prevents use of |
| ``if (IS_ENABLED(CONFIG_FOO)) {}`` as an alternative to preprocessor |
| conditionals when the code path should change based on the selected options. |
| |
| .. _coding_guideline_inclusive_language: |
| |
| Rule A.2: Inclusive Language |
| ============================ |
| |
| Severity |
| -------- |
| |
| Required |
| |
| Description |
| ----------- |
| |
| Do not introduce new usage of offensive terms listed below. This rule applies |
| but is not limited to source code, comments, documentation, and branch names. |
| Replacement terms may vary by area or subsystem, but should aim to follow |
| updated industry standards when possible. |
| |
| Exceptions are allowed for maintaining existing implementations or adding new |
| implementations of industry standard specifications governed externally to the |
| Zephyr Project. |
| |
| Existing usage is recommended to change as soon as updated industry standard |
| specifications become available or new terms are publicly announced by the |
| governing body, or immediately if no specifications apply. |
| |
| .. list-table:: |
| :header-rows: 1 |
| |
| * - Offensive Terms |
| - Recommended Replacements |
| |
| * - ``{master,leader} / slave`` |
| - - ``{primary,main} / {secondary,replica}`` |
| - ``{initiator,requester} / {target,responder}`` |
| - ``{controller,host} / {device,worker,proxy,target}`` |
| - ``director / performer`` |
| - ``central / peripheral`` |
| |
| * - ``blacklist / whitelist`` |
| - * ``denylist / allowlist`` |
| * ``blocklist / allowlist`` |
| * ``rejectlist / acceptlist`` |
| |
| * - ``grandfather policy`` |
| - * ``legacy`` |
| |
| * - ``sanity`` |
| - * ``coherence`` |
| * ``confidence`` |
| |
| |
| Rationale |
| --------- |
| |
| Offensive terms do not create an inclusive community environment and therefore |
| violate the Zephyr Project `Code of Conduct`_. This coding rule was inspired by |
| a similar rule in `Linux`_. |
| |
| .. _Code of Conduct: https://github.com/zephyrproject-rtos/zephyr/blob/main/CODE_OF_CONDUCT.md |
| .. _Linux: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=49decddd39e5f6132ccd7d9fdc3d7c470b0061bb |
| |
| Status |
| ------ |
| |
| Related GitHub Issues and Pull Requests are tagged with the `Inclusive Language Label`_. |
| |
| .. list-table:: |
| :header-rows: 1 |
| |
| * - Area |
| - Selected Replacements |
| - Status |
| |
| * - :ref:`Bluetooth <bluetooth_api>` |
| - See `Bluetooth Appropriate Language Mapping Tables`_ |
| - |
| |
| * - CAN |
| - This `CAN in Automation Inclusive Language news post`_ has a list of general |
| recommendations. See `CAN in Automation Inclusive Language`_ for terms to |
| be used in specification document updates. |
| - |
| |
| * - eSPI |
| - * ``master / slave`` => ``controller / target`` |
| - Refer to `eSPI Specification`_ for new terminology |
| |
| * - gPTP |
| - * ``master / slave`` => TBD |
| - |
| |
| * - :ref:`i2c_api` |
| - * ``master / slave`` => TBD |
| - NXP publishes the `I2C Specification`_ and has selected ``controller / |
| target`` as replacement terms, but the timing to publish an announcement |
| or new specification is TBD. Zephyr will update I2C when replacement |
| terminology is confirmed by a public announcement or updated |
| specification. |
| |
| See :github:`Zephyr issue 27033 <27033>`. |
| |
| * - :ref:`i2s_api` |
| - * ``master / slave`` => TBD |
| - |
| |
| * - SMP/AMP |
| - * ``master / slave`` => TBD |
| - |
| |
| * - :ref:`spi_api` |
| - * ``master / slave`` => ``controller / peripheral`` |
| * ``MOSI / MISO / SS`` => ``SDO / SDI / CS`` |
| - The Open Source Hardware Association has selected these replacement |
| terms. See `OSHWA Resolution to Redefine SPI Signal Names`_ |
| |
| * - :ref:`twister_script` |
| - * ``platform_whitelist`` => ``platform_allow`` |
| * ``sanitycheck`` => ``twister`` |
| - |
| |
| .. _Inclusive Language Label: https://github.com/zephyrproject-rtos/zephyr/issues?q=label%3A%22Inclusive+Language%22 |
| .. _I2C Specification: https://www.nxp.com/docs/en/user-guide/UM10204.pdf |
| .. _Bluetooth Appropriate Language Mapping Tables: https://specificationrefs.bluetooth.com/language-mapping/Appropriate_Language_Mapping_Table.pdf |
| .. _OSHWA Resolution to Redefine SPI Signal Names: https://www.oshwa.org/a-resolution-to-redefine-spi-signal-names/ |
| .. _CAN in Automation Inclusive Language news post: https://www.can-cia.org/news/archive/view/?tx_news_pi1%5Bnews%5D=699&tx_news_pi1%5Bday%5D=6&tx_news_pi1%5Bmonth%5D=12&tx_news_pi1%5Byear%5D=2020&cHash=784e79eb438141179386cf7c29ed9438 |
| .. _CAN in Automation Inclusive Language: https://can-newsletter.org/canopen/categories/ |
| .. _eSPI Specification: https://downloadmirror.intel.com/27055/327432%20espi_base_specification%20R1-5.pdf |
| |
| |
| Rule A.3: Macro name collisions |
| =============================== |
| |
| Severity |
| -------- |
| |
| Required |
| |
| Description |
| ----------- |
| |
| Macros with commonly used names such as ``MIN``, ``MAX``, ``ARRAY_SIZE``, must |
| not be modified or protected to avoid name collisions with other |
| implementations. In particular, they must not be prefixed to place them in a |
| Zephyr-specific namespace, re-defined using ``#undef``, or conditionally |
| excluded from compilation using ``#ifndef``. Instead, if a conflict arises with |
| an existing definition originating from a :ref:`module <modules>`, the module's |
| code itself needs to be modified (ideally upstream, alternatively via a change |
| in Zephyr's own fork). |
| This rule applies to Zephyr as a project in general, regardless of the time of |
| introduction of the macro or its current name in the tree. If a macro name is |
| commonly used in several other well-known open source projects then the |
| implementation in Zephyr should use that name. While there is a subjective and |
| non-measurable component to what "commonly used" means, the ultimate goal is |
| to offer users familiar macros. |
| Finally, this rule applies to inter-module name collisions as well: in that case |
| both modules, prior to their inclusion, should be modified to use |
| module-specific versions of the macro name that collides. |
| |
| Rationale |
| --------- |
| |
| Zephyr is an RTOS that comes with additional functionality and dependencies in |
| the form of modules. Those modules are typically independent projects that may |
| use macro names that can conflict with other modules or with Zephyr itself. |
| Since, in the context of this documentation, Zephyr is considered the central or |
| main project, it should implement the non-namespaced versions of the |
| macros. Given that Zephyr uses a fork of the corresponding upstream for each |
| module, it is always possible to patch the macro implementation in each module |
| to avoid collisions. |
| |
| .. _coding_guideline_libc_usage_restrictions_in_zephyr_kernel: |
| |
| Rule A.4: C Standard Library Usage Restrictions in Zephyr Kernel |
| ================================================================ |
| |
| Severity |
| -------- |
| |
| Required |
| |
| Description |
| ----------- |
| |
| The use of the C standard library functions and macros in the Zephyr kernel |
| shall be limited to the following functions and macros from the ISO/IEC |
| 9899:2011 standard, also known as C11, and their extensions: |
| |
| .. csv-table:: List of allowed libc functions and macros in the Zephyr kernel |
| :header: Function,Source |
| :widths: auto |
| |
| abort(),ISO/IEC 9899:2011 |
| abs(),ISO/IEC 9899:2011 |
| aligned_alloc(),ISO/IEC 9899:2011 |
| assert(),ISO/IEC 9899:2011 |
| atoi(),ISO/IEC 9899:2011 |
| bsearch(),ISO/IEC 9899:2011 |
| calloc(),ISO/IEC 9899:2011 |
| exit(),ISO/IEC 9899:2011 |
| fprintf(),ISO/IEC 9899:2011 |
| fputc(),ISO/IEC 9899:2011 |
| fputs(),ISO/IEC 9899:2011 |
| free(),ISO/IEC 9899:2011 |
| fwrite(),ISO/IEC 9899:2011 |
| gmtime(),ISO/IEC 9899:2011 |
| isalnum(),ISO/IEC 9899:2011 |
| isalpha(),ISO/IEC 9899:2011 |
| iscntrl(),ISO/IEC 9899:2011 |
| isdigit(),ISO/IEC 9899:2011 |
| isgraph(),ISO/IEC 9899:2011 |
| isprint(),ISO/IEC 9899:2011 |
| isspace(),ISO/IEC 9899:2011 |
| isupper(),ISO/IEC 9899:2011 |
| isxdigit(),ISO/IEC 9899:2011 |
| labs(),ISO/IEC 9899:2011 |
| llabs(),ISO/IEC 9899:2011 |
| malloc(),ISO/IEC 9899:2011 |
| memchr(),ISO/IEC 9899:2011 |
| memcmp(),ISO/IEC 9899:2011 |
| memcpy(),ISO/IEC 9899:2011 |
| memmove(),ISO/IEC 9899:2011 |
| memset(),ISO/IEC 9899:2011 |
| perror(),ISO/IEC 9899:2011 |
| printf(),ISO/IEC 9899:2011 |
| putc(),ISO/IEC 9899:2011 |
| putchar(),ISO/IEC 9899:2011 |
| puts(),ISO/IEC 9899:2011 |
| qsort(),ISO/IEC 9899:2011 |
| rand(),ISO/IEC 9899:2011 |
| realloc(),ISO/IEC 9899:2011 |
| snprintf(),ISO/IEC 9899:2011 |
| sprintf(),ISO/IEC 9899:2011 |
| sqrt(),ISO/IEC 9899:2011 |
| sqrtf(),ISO/IEC 9899:2011 |
| srand(),ISO/IEC 9899:2011 |
| strcat(),ISO/IEC 9899:2011 |
| strchr(),ISO/IEC 9899:2011 |
| strcmp(),ISO/IEC 9899:2011 |
| strcpy(),ISO/IEC 9899:2011 |
| strcspn(),ISO/IEC 9899:2011 |
| strerror(),ISO/IEC 9899:2011 |
| strlen(),ISO/IEC 9899:2011 |
| strncat(),ISO/IEC 9899:2011 |
| strncmp(),ISO/IEC 9899:2011 |
| strncpy(),ISO/IEC 9899:2011 |
| `strnlen()`_,POSIX.1-2008 |
| strrchr(),ISO/IEC 9899:2011 |
| strspn(),ISO/IEC 9899:2011 |
| strstr(),ISO/IEC 9899:2011 |
| strtol(),ISO/IEC 9899:2011 |
| strtoll(),ISO/IEC 9899:2011 |
| strtoul(),ISO/IEC 9899:2011 |
| strtoull(),ISO/IEC 9899:2011 |
| time(),ISO/IEC 9899:2011 |
| tolower(),ISO/IEC 9899:2011 |
| toupper(),ISO/IEC 9899:2011 |
| vfprintf(),ISO/IEC 9899:2011 |
| vprintf(),ISO/IEC 9899:2011 |
| vsnprintf(),ISO/IEC 9899:2011 |
| vsprintf(),ISO/IEC 9899:2011 |
| |
| All of the functions listed above must be implemented by the |
| :ref:`minimal libc <c_library_minimal>` to ensure that the Zephyr kernel can |
| build with the minimal libc. |
| |
| In addition, any functions from the above list that are not part of the |
| ISO/IEC 9899:2011 standard must be implemented by the |
| :ref:`common libc <c_library_common>` to ensure their availability across |
| multiple C standard libraries. |
| |
| Introducing new C standard library functions to the Zephyr kernel is allowed |
| with justification given that the above requirements are satisfied. |
| |
| Note that the use of the functions listed above are subject to secure and safe |
| coding practices and it should not be assumed that their use in the Zephyr |
| kernel is unconditionally permitted by being listed in this rule. |
| |
| The "Zephyr kernel" in this context consists of the following components: |
| |
| * Kernel (:file:`kernel`) |
| * OS Library (:file:`lib/os`) |
| * Architecture Port (:file:`arch`) |
| * Logging Subsystem (:file:`subsys/logging`) |
| |
| Rationale |
| --------- |
| |
| Zephyr kernel must be able to build with the |
| :ref:`minimal libc <c_library_minimal>`, a limited C standard library |
| implementation that is part of the Zephyr RTOS and maintained by the Zephyr |
| Project, to allow self-contained testing and verification of the kernel and |
| core OS services. |
| |
| In order to ensure that the Zephyr kernel can build with the minimal libc, it |
| is necessary to restrict the use of the C standard library functions and macros |
| in the Zephyr kernel to the functions and macros that are available as part of |
| the minimal libc. |
| |
| Rule A.5: C Standard Library Usage Restrictions in Zephyr Codebase |
| ================================================================== |
| |
| Severity |
| -------- |
| |
| Required |
| |
| Description |
| ----------- |
| |
| The use of the C standard library functions and macros in the Zephyr codebase |
| shall be limited to the functions, excluding the Annex K "Bounds-checking |
| interfaces", from the ISO/IEC 9899:2011 standard, also known as C11, unless |
| exempted by this rule. |
| |
| The "Zephyr codebase" in this context refers to all embedded source code files committed |
| to the `main Zephyr repository`_, except the Zephyr kernel as defined by the |
| :ref:`coding_guideline_libc_usage_restrictions_in_zephyr_kernel`. |
| With embedded source code we refer to code which is meant to be executed in embedded |
| targets, and therefore excludes host tooling, and code specific for the |
| :ref:`native <boards_posix>` test targets. |
| |
| The following non-ISO 9899:2011, hereinafter referred to as non-standard, |
| functions and macros are exempt from this rule and allowed to be used in the |
| Zephyr codebase: |
| |
| .. csv-table:: List of allowed non-standard libc functions |
| :header: Function,Source |
| :widths: auto |
| |
| `gmtime_r()`_,POSIX.1-2001 |
| `strnlen()`_,POSIX.1-2008 |
| `strtok_r()`_,POSIX.1-2001 |
| |
| All non-standard functions and macros listed above must be implemented by the |
| :ref:`common libc <c_library_common>` in order to make sure that these |
| functions can be made available when using a C standard library that does not |
| implement these functions. |
| |
| Adding a new non-standard function from common C standard libraries to the |
| above list is allowed with justification, given that the above requirement is |
| satisfied. However, when there exists a standard function that is functionally |
| equivalent, the standard function shall be used. |
| |
| Rationale |
| --------- |
| |
| Some C standard libraries, such as Newlib and Picolibc, include additional |
| functions and macros that are defined by the standards and de-facto standards |
| that extend the ISO C standard (e.g. POSIX, Linux). |
| |
| The ISO/IEC 9899:2011 standard does not require C compiler toolchains to |
| include the support for these non-standard functions, and therefore using |
| these functions can lead to compatibility issues with the third-party |
| toolchains that come with their own C standard libraries. |
| |
| .. _main Zephyr repository: https://github.com/zephyrproject-rtos/zephyr |
| .. _gmtime_r(): https://pubs.opengroup.org/onlinepubs/9699919799/functions/gmtime_r.html |
| .. _strnlen(): https://pubs.opengroup.org/onlinepubs/9699919799/functions/strlen.html |
| .. _strtok_r(): https://pubs.opengroup.org/onlinepubs/9699919799/functions/strtok.html |
