Description

The strerror() function maps the number in errnum to a message string. Typically, the values for errnum come from errno, but strerror() shall map any value of type int to a message.

Return value

The strerror() function returns a pointer to the string, the contents of which are locale- specific. The array pointed to shall not be modified by the program, but may be overwritten by a subsequent call to the strerror() function.

Prototype

Declared in string.h

The C89/C99 prototype is:

char *strerror(int errnum);

Implementation

In standard C, this can be implemented as:

char *strerror(int errnum)
{
    /*
        That is actually interpreting the standard by the letter, not intent.
        We only know about the "C" locale, no more. That's the only mandatory locale anyway.
    */
    return errnum ? "There was an error, but I didn't crash yet!" : "No error.";
}

Compilable unit, portable C90 in implementation namespace; public domain; past reviewers: none; current reviews: none

References

The C Standard, 7.21.6.2 (C99 numbering)