What does (void)var actually do?

Question

Consider the following main():

int main(int argc, char *argv[])
{
    return (0);
}

Upon compilation with cc -Wall -Wext

Answer 1

As other persons correctly noted, It just suppresses a compiler warning about unused variable in your code. Btw, Win32 has defined UNREFERENCED_PARAMETER macro to reach this goal. My suggestion to make something like that in your code:

#ifdef _WIN32
# define UNUSED(x) UNREFERENCED_PARAMETER(x)
#else
# define UNUSED(x) (void) x
#endif