Re: detect presence/version of nptl

> From: Ulrich Drepper <[email protected]>
> Date: Sun, 16 Feb 2003 12:59:19 -0800
> 
> I've been asked to provide a mechanism to dynamically detect whether
> nptl is used and which version.
> 
> With the current CVS sources you can use confstr() with the key
> _CS_GNU_LIBPTHREAD_VERSION to get just that information.  It'll return a
> string like "NPTL 0.22" or "linuxthreads-0.10".  This should provide all
> the info you need.  There is also _CS_GNU_LIBC_VERSION for those who
> need that.

How about binaries built with headers from glibc-2.2.x that have to
run with any one of glibc-2.2.x-LT and glibc-2.3.x-{LT,NPTL}.  Is
there a reliable way for such an application to determine at runtime
if it is running with NPTL?

On a related note, if anyone from redhat who does builds is listening,
confstr(_CS_GNU_LIBPTHREAD_VERSION) doesn't work right on RedHat
rawhide RPMS, don't have RedHat 9 here.
        
$ rpm -q glibc nptl-devel
glibc-2.3.2-11.9
nptl-devel-2.3.2-11.9
$ cat conf.c
#include <pthread.h>
#include <stdio.h>
#include <unistd.h>

int main()
{
    char v[64];
    confstr(_CS_GNU_LIBPTHREAD_VERSION, v, sizeof(v));
    printf("version: %s\n", v);
    return 0;
}
$ cc conf.c -lpthread
$ (export LD_LIBRARY_PATH=/lib/i686; ldd ./a.out | grep thread; ./a.out)
        libpthread.so.0 => /lib/i686/libpthread.so.0 (0x40017000)
version: NPTL 0.29