4.9.	How can I find out which version of glibc I am using in the moment?

{UD} If you want to find out about the version from the command line simply
run the libc binary.  This is probably not possible on all platforms but
where it is simply locate the libc DSO and start it as an application.  On
Linux like

	/lib/libc.so.6

This will produce all the information you need.

What always will work is to use the API glibc provides.  Compile and run the
following little program to get the version information:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include <stdio.h>
#include <gnu/libc-version.h>
int main (void) { puts (gnu_get_libc_version ()); return 0; }
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This interface can also obviously be used to perform tests at runtime if
this should be necessary.