assert() with message

I saw somewhere assert used with a message in the following way:

assert(("message", condition));

This seems to work great, except that gcc throws the following warning:

warning: left-hand operand of comma expression has no effect

How can I stop the warning?

Solution 1:

Use -Wno-unused-value to stop the warning; (the option -Wall includes -Wunused-value).

I think even better is to use another method, like

assert(condition && "message");

Solution 2:

Try:

#define assert__(x) for ( ; !(x) ; assert(x) )

use as such:

assert__(x) {
    printf("assertion will fail\n"); 
}

Will execute the block only when assert fails.

IMPORTANT NOTE: This method will evaluate expression x twice, in case x evaluates to false! (First time, when the for loop is checking its condition; second time, when the assert is evaluating the passed expression!)