# Toolchain This module defines a toolchain abstraction layer through macros. ## Summary Usage:
``` typedef OT_TOOL_PACKED_BEGIN struct { char mField1; union { char mField2; long mField3; } OT_TOOL_PACKED_FIELD; } OT_TOOL_PACKED_END packed_struct_t; ```
| ### Macros || |---|---| | `https://openthread.io/reference/group/plat-toolchain#group__plat-toolchain_1gaa6db3390ea1a7ab5d9cc41ee92847e76 __VA_ARGS__` | | | `https://openthread.io/reference/group/plat-toolchain#group__plat-toolchain_1gab7d13249e3f89f28bf90650780ebd004 do \ { \ } while (false) /* fallthrough */` | Suppress fall through warning in specific compiler. | | `https://openthread.io/reference/group/plat-toolchain#group__plat-toolchain_1ga78619f2131e14bb383ef31d5a56bdbc4` | Compiler-specific indication that a class or struct is a resource owner for lifetime safety analysis. | | `https://openthread.io/reference/group/plat-toolchain#group__plat-toolchain_1ga067d4d11c7e7b84560bd8af7edbbf4c4` | Compiler-specific indication that a class or struct is a non-owning view or pointer for lifetime safety analysis. | | `https://openthread.io/reference/group/plat-toolchain#group__plat-toolchain_1gaaeff20b2666903cddb27860cf45ca707` | Compiler-specific indication that a function or method return value's lifetime is bound to a parameter or `this`. | | `https://openthread.io/reference/group/plat-toolchain#group__plat-toolchain_1ga85de426d72fe7c26a0fa927ed51db39d` | Compiler-specific indication that a class or enum must be used when it is the return value of a function. | | `https://openthread.io/reference/group/plat-toolchain#group__plat-toolchain_1gae629cb38422619fa287047f5d859d872` | Compiler-specific indication that a pointer or reference parameter does not escape the function scope. | | `https://openthread.io/reference/group/plat-toolchain#group__plat-toolchain_1gaa846557e3320c6c3a8a0448f1d1f0bab` | | | `https://openthread.io/reference/group/plat-toolchain#group__plat-toolchain_1ga5d2b35a947d54bcbd4e9f539e8dad768` | | | `https://openthread.io/reference/group/plat-toolchain#group__plat-toolchain_1gaba6ad63129c3a790957a9b149a65891b` | Compiler-specific indication that a class or struct must be byte packed. | | `https://openthread.io/reference/group/plat-toolchain#group__plat-toolchain_1ga3a18bfefd8517f5653568f3b8423ed40` | Indicate to the compiler a nested struct or union to be packed within byte packed class or struct. | | `https://openthread.io/reference/group/plat-toolchain#group__plat-toolchain_1gabe6a7eade7833871637a0c4efe629404` | Specifies that a function or method takes `printf` style arguments and should be type-checked against a format string. | | `https://openthread.io/reference/group/plat-toolchain#group__plat-toolchain_1gafa4fa6f7590e3c3c45f69d2f9f1bca43` | Compiler-specific weak symbol modifier. | | `https://openthread.io/reference/group/plat-toolchain#group__plat-toolchain_1gab3be7baad123fa22d83d942794fe71d7 CODE` | Suppress Unreachable code warning in specific toolchains. | | `https://openthread.io/reference/group/plat-toolchain#group__plat-toolchain_1ga1f82d697553f7df5589668e481738e8c do \ { \ (void)(VARIABLE); \ } while (false)` | Suppress unused variable warning in specific toolchains. | ## Macros ### OT_APPLE_IGNORE_GNU_FOLDING_CONSTANT ``` OT_APPLE_IGNORE_GNU_FOLDING_CONSTANT __VA_ARGS__ ``` ### OT_FALL_THROUGH ``` OT_FALL_THROUGH do \ { \ } while (false) /* fallthrough */ ``` Suppress fall through warning in specific compiler. ### OT_GSL_OWNER ``` OT_GSL_OWNER ``` Compiler-specific indication that a class or struct is a resource owner for lifetime safety analysis. ### OT_GSL_POINTER ``` OT_GSL_POINTER ``` Compiler-specific indication that a class or struct is a non-owning view or pointer for lifetime safety analysis. ### OT_LIFETIME_BOUND ``` OT_LIFETIME_BOUND ``` Compiler-specific indication that a function or method return value's lifetime is bound to a parameter or `this`. ### OT_MUST_USE_RESULT ``` OT_MUST_USE_RESULT ``` Compiler-specific indication that a class or enum must be used when it is the return value of a function.
> [!NOTE] > **Note:** This is currently only available with clang (C++17 implements it as attribute \[\[nodiscard\]\]). > [!NOTE] > **Note:** To suppress the 'unused-result' warning/error, please use the '-Wno-unused-result' compiler option.
### OT_NOESCAPE ``` OT_NOESCAPE ``` Compiler-specific indication that a pointer or reference parameter does not escape the function scope. ### OT_SUPPRESS_GCC_STRING_OP_BEGIN ``` OT_SUPPRESS_GCC_STRING_OP_BEGIN ``` ### OT_SUPPRESS_GCC_STRING_OP_END ``` OT_SUPPRESS_GCC_STRING_OP_END ``` ### OT_TOOL_PACKED_BEGIN ``` OT_TOOL_PACKED_BEGIN ``` Compiler-specific indication that a class or struct must be byte packed. ### OT_TOOL_PACKED_FIELD ``` OT_TOOL_PACKED_FIELD ``` Indicate to the compiler a nested struct or union to be packed within byte packed class or struct. ### OT_TOOL_PRINTF_STYLE_FORMAT_ARG_CHECK ``` OT_TOOL_PRINTF_STYLE_FORMAT_ARG_CHECK ``` Specifies that a function or method takes `printf` style arguments and should be type-checked against a format string. Must be added after the function/method declaration. For example: `void MyPrintf(void *aObject, const char *aFormat, ...) https://openthread.io/reference/group/plat-toolchain#group__plat-toolchain_1gabe6a7eade7833871637a0c4efe629404;` The two argument index values indicate format string and first argument to check against it. They start at index 1 for the first parameter in a function and at index 2 for the first parameter in a method.
Details Parameters `[in] aFmtIndex` The argument index of the format string. `[in] aStartIndex` The argument index of the first argument to check against the format string. ### OT_TOOL_WEAK ``` OT_TOOL_WEAK ``` Compiler-specific weak symbol modifier. ### OT_UNREACHABLE_CODE ``` OT_UNREACHABLE_CODE CODE ``` Suppress Unreachable code warning in specific toolchains. ### OT_UNUSED_VARIABLE ``` OT_UNUSED_VARIABLE do \ { \ (void)(VARIABLE); \ } while (false) ``` Suppress unused variable warning in specific toolchains. ## Resources OpenThread API Reference topics originate from the source code, available on [GitHub](https://github.com/openthread/openthread/tree/main/include/openthread). For more information, or to contribute to our documentation, refer to [Resources](https://openthread.io/resources).