Thread: how to clean errno?

Originally Posted by MK27

so generally speaking there is no reason to set errno to zero.

There is: the C standard library contains some functions that indicate an error only by setting errno. Hence, if you don't set errno to 0 right before the function call, you can't tell whether errno has been modified by the function or not.

By the way, the standard guarantees that no library function will ever set errno to 0.

Greets,
Philip

Originally Posted by Brafil

Of course, that looks like a mismatch in design. well, what solution would you propose in that case?

Write to the ISO/IEEE people and tell them what a bunch of incompetent jerks they are and how they have ruined your life.

Originally Posted by Brafil

Of course, that looks like a mismatch in design. well, what solution would you propose in that case?

Code:

errno = 0;
library_call_with_a_bad_design();

switch(errno) {
        /* ... */
                break;
        case 0:
                /* everything's ok */
                break;
        default:
                /* uncatched error */
                break;
}

Greets,
Philip