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csuppress-warnings

Best way to suppress C warning "Unused variable x"?

What is the best/neatest way to suppress a C compiler (for example GCC) like "Unused variable x" warning?

GCC's doumentation explains

-Wunused-variable
Warn whenever a local variable or non-constant static variable is unused aside from its declaration

I don't want to give any certain flags to my compiler to remove all these warnings, just for special cases.

Solution

  • I found an article, http://sourcefrog.net/weblog/software/languages/C/unused.html, that explains UNUSED. It is interesting that the author also mangles the unused variable name, so you can't inadvertently use it in the future.

    Excerpt:

    #ifdef UNUSED
#elif defined(__GNUC__)
# define UNUSED(x) UNUSED_ ## x __attribute__((unused))
#elif defined(__LCLINT__)
# define UNUSED(x) /*@unused@*/ x
#else
# define UNUSED(x) x
#endif

void dcc_mon_siginfo_handler(int UNUSED(whatsig))