How to obtaing glibc version

To obtain glibc version You can write and compile following program:
gcc -o get_glibc get_glibc.c

#include <stdio.h>
#include <gnu/libc-version.h>

int main(void) {
    puts(gnu_get_libc_version());
    return 0;
}

After executing the program will write out current glibc version on standard output.

Also the current glibc version you can obtain by issuing following command: ldd --version | head -n1 | cut -d" " -f2-