Make CASSERT() macro callable from anywhere

The CASSERT() macro introduces a typedef for the sole purpose of
triggering a compilation error if the condition to check is false.
This typedef is not used afterwards. As a consequence, when the
CASSERT() macro is called from withing a function block, the compiler
complains and outputs the following error message:

  error: typedef 'msg' locally defined but not used [-Werror=unused-local-typedefs]

This patch adds the "unused" attribute for the aforementioned
typedef. This silences the compiler warning and thus makes the
CASSERT() macro callable from within function blocks as well.

Change-Id: Ie36b58fcddae01a21584c48bb6ef43ec85590479
This commit is contained in:
Sandrine Bailleux 2015-10-14 16:00:23 +01:00
parent a3a348993a
commit c17a4dc34c
1 changed files with 5 additions and 2 deletions

View File

@ -34,9 +34,12 @@
/*******************************************************************************
* Macro to flag a compile time assertion. It uses the preprocessor to generate
* an invalid C construct if 'cond' evaluates to false.
* The following compilation error is triggered if the assertion fails:
* The following compilation error is triggered if the assertion fails:
* "error: size of array 'msg' is negative"
* The 'unused' attribute ensures that the unused typedef does not emit a
* compiler warning.
******************************************************************************/
#define CASSERT(cond, msg) typedef char msg[(cond) ? 1 : -1]
#define CASSERT(cond, msg) \
typedef char msg[(cond) ? 1 : -1] __attribute__((unused))
#endif /* __CASSERT_H__ */