Re: Bug#162576: marked as done (libc6-dev: errno is a function call in non-threaded program)

[Ben Collins <bcollins@debian.org>]

> _LIBC is only defined when _BUILDING_ glibc.  And _LIBC_REENTRANT !=
> _REENTRANT.
> 
> Any application code will have !_LIBC.

Doh, yeah, that was too quick I guess.

I just compiled this test program to be sure:

#include <errno.h>
int main() {
  int i = errno;
  return i;
}

and:

hopper:~$ gcc -o test test.c
hopper:~$ objdump --dynamic-syms test | grep errno
00021954      DF *UND*  00000024  GLIBC_2.0   __errno_location

Question is, is it really that much overhead? I can't see many
applications having references to errno become a bottleneck for
performance. If they do, then they should probably be rewritten anyway
:)


Ben

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