Re: glibc strerrorname_np

[Florian Weimer <fweimer@redhat.com>]

* Jonny Grant:

> I noticed on the man page it may return NULL, which is a shame, as then it means we always need to check that before using in every printf etc :-
>
> printf("err %s\n", strerrorname_np(myerr)?strerrorname_np(myerr), "Unknown err");

We can add %#m to printf for this use case.  It would print the errno
constant if known, or a number otherwise.  To use it, errno needs to be
assigned before calling printf.  Printing multiple error codes would not
be possible directly, but such usage is quite rare.

On older glibc, it prints the (translated) string, which is better than
nothing.

Thanks,
Florian