On Thu, Jun 9, 2011 at 11:23 AM, Jonathan Wakely <jwakely.gcc@xxxxxxxxx> wrote: >> - disabling the warning would (I guess) also affect when checking >> addresses without using macros > > Not if you do it locally in the macro only, using _Pragma > http://gcc.gnu.org/onlinedocs/gcc-4.6.0/gcc/Diagnostic-Pragmas.html Thank you for the pointers. Today I tried again to use it, but I'm unable to get it right. I understood that I should use _Pragma inside my `function-style macro', but I get errors. I assume because I'm trying to use _Pragma `inside' an expression. I'm sorry to bother you again but could you please give an concrete example or implement/fix my example? The example macro is getLen (implemented as macro because some compilers may not `inline' correctly automatically and do not offer a way to explicitely do so). The usage is: len = getLen(&stack_var); Here some code I tried: /* with "len = getLen(&bb);": * (68 of 85): 4: warning: the comparison will always evaluate as 'true' * for the address of 'ref' will never be NULL [-Waddress] */ struct bb_s { void *m; size_t l; }; /* The macro that I would like to use without warnings: */ #define getLen(bb) (size_t)(((bb) != NULL ? (bb)->l : 0)) #if 0 /* (11 of 17): 1: error: expected expression before '#pragma' */ #define getLen(bb) \ _Pragma ("GCC diagnostic push") \ _Pragma ("GCC diagnostic ignored \"-Waddress\"") \ (size_t)(((bb) != NULL ? (bb)->l : 0)) \ _Pragma ("GCC diagnostic pop") #endif void func(void); void func(void) { struct bb_s bb = { 0 }; size_t len; /* This is the usage I would like to have without warnings */ len = getLen(&bb); assert(len == 0); } Have a nice weekend everyone, Steffen
