pointer/integer type mismatch in conditional expression

Question

gcc 4.7.2 c89

Hello,

I am getting the following warning:

pointer/integer type mismatch in conditional expression


        

Answer 1

Check whether you have included <string.h> header. If not, the return value of strerror may be considered as an integer value. It would explain why the program runs ok (the linker can find a matched function named strerror, because the C standard library is linked by default), whereas the compiler reports a warning.