Message text for ferror() return value

Question

How can I get the message for error codes returned by int ferror(FILE*)? For errno there is the char * strerror(int). What is it for codes returned by ferror? If char * strerror(int) is good for that too, then I need a reference for it (I failed to find any indicator for this case).

Answer 1

From this reference page:

The ferror() function shall test the error indicator for the stream pointed to by stream.

This means that ferror returns a boolean that tells you if there is an error or not, nothing more. But according to the POSIX specification the value of errno will contain an error code in case of a failure.

Answer 2

The library libexplain can return strings for the ferror. https://linux.die.net/man/3/explain_ferror From the docs:

if (ferror(fp) < 0)
{
    fprintf(stderr, "%s\n", explain_ferror(fp));
    exit(EXIT_FAILURE);
}