I have two gcc compilers installed on my system, one is gcc 4.1.2 (default) and the other is gcc 4.4.4. How can I check the libc version used by gcc 4.4.4, because /lib/libc.so.6 shows the glibc used by gcc 4.1.2, since it is the default compiler.
8 Answers
Write a test program (name it for example glibc-version.c):
#include <stdio.h>
#include <stdlib.h>
#include <gnu/libc-version.h>
int main(int argc, char *argv[]) { printf("GNU libc version: %s\n", gnu_get_libc_version()); exit(EXIT_SUCCESS);
}and compile it with the gcc-4.4 compiler:
gcc-4.4 glibc-version.c -o glibc-versionWhen you execute ./glibc-version the used glibc version is shown.
even easier
use ldd --version
This should return the glibc version being used i.e.
$ ldd --version
ldd (GNU libc) 2.17
Copyright (C) 2012 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO...
which is the same result as running my libc library
$ /lib/libc.so.6
GNU C Library (GNU libc) stable release version 2.17, by Roland McGrath et al.
Copyright (C) 2012 Free Software Foundation, Inc.
This is free software; see the source for copying conditions....
1Use -print-file-name gcc option:
$ gcc -print-file-name=libc.so
/usr/lib/gcc/x86_64-redhat-linux/4.5.1/../../../../lib64/libc.soThat gives the path. Now:
$ file /usr/lib/gcc/x86_64-redhat-linux/4.5.1/../../../../lib64/libc.so
/usr/lib/gcc/x86_64-redhat-linux/4.5.1/../../../../lib64/libc.so: ASCII C program text
$ cat /usr/lib/gcc/x86_64-redhat-linux/4.5.1/../../../../lib64/libc.so
/* GNU ld script Use the shared library, but some functions are only in the static library, so try that secondarily. */
OUTPUT_FORMAT(elf64-x86-64)
GROUP ( /lib64/libc.so.6 /usr/lib64/libc_nonshared.a AS_NEEDED ( /lib64/ld-linux-x86-64.so.2 ) )Looks like a linker script. libc is special on Linux in that it can be executed:
$ /lib64/libc.so.6
GNU C Library stable release version 2.13, by Roland McGrath et al.
Copyright (C) 2011 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
Compiled by GNU CC version 4.5.1 20100924 (Red Hat 4.5.1-4).
Compiled on a Linux 2.6.35 system on 2011-08-05.
Available extensions: Support for some architectures added on, not maintained in glibc core. The C stubs add-on version 2.1.2. crypt add-on version 2.1 by Michael Glad and others GNU Libidn by Simon Josefsson Native POSIX Threads Library by Ulrich Drepper et al BIND-8.2.3-T5B RT using linux kernel aio
libc ABIs: UNIQUE IFUNC
For bug reporting instructions, please see:
<gnu_get_libc_version identifies the runtime version of the GNU C Library.
If what you care about is the compile-time version (that is, the version that provided the headers in /usr/include), you should look at the macros __GLIBC__ and __GLIBC_MINOR__. These expand to positive integers, and will be defined as a side-effect of including any header file provided by the GNU C Library; this means you can include a standard header, and then use #ifdef __GLIBC__ to decide whether you can include a nonstandard header like gnu/libc-version.h.
Expanding the test program from the accepted answer:
#include <stdio.h>
#ifdef __GLIBC__
#include <gnu/libc-version.h>
#endif
int
main(void)
{
#ifdef __GLIBC__ printf("GNU libc compile-time version: %u.%u\n", __GLIBC__, __GLIBC_MINOR__); printf("GNU libc runtime version: %s\n", gnu_get_libc_version()); return 0;
#else puts("Not the GNU C Library"); return 1;
#endif
}When I compile and run this program on the computer I'm typing this answer on (which is a Mac) it prints
Not the GNU C Librarybut when compiled and run on a nearby Linux box it prints
GNU libc compile-time version: 2.24
GNU libc runtime version: 2.24Under normal circumstances, the "runtime" version could be bigger than the "compile-time" version, but never smaller. The major version number is unlikely ever to change again (the last time it changed was the "libc6 transition" in 1997).
If you would prefer a shell 'one-liner' to dump these macros, use:
echo '#include <errno.h>' | gcc -xc - -E -dM | grep -E '^#define __GLIBC(|_MINOR)__ ' | sortThe grep pattern is chosen to match only the two macros that are relevant, because there are dozens of internal macros named __GLIBC_somethingorother that you don't want to have to read through.
I doubt if you have more than one glibc installed in your system.But ldd -v <path/to/gcc-4.x> should give you the glibc used.
The easiest way is to use ldd which comes with glibc
Just run this command ldd --version :
dina@dina-X450LA:~$ ldd --version
ldd (Ubuntu GLIBC 2.23-0ubuntu9) 2.23
Copyright (C) 2016 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Written by Roland McGrath and Ulrich Drepper.Their is two additional ways to find out the glibc version:
Check the version of the installed glibc rpm package : this by runing this command
rpm -q glibcCheck the version of the used libc.so file. This way is a little bit more difficult. You can check it in this link: Linux: Check the glibc version
You can use strings command to check GLIBC version of compiler. Highest version is applicable.
ubuntu1604:extra$ strings ./arm-unknown-linux-gnueabi/bin/arm-unknown-linux-gnueabi-gcc | grep GLIBC GLIBC_2.3 GLIBC_2.8 GLIBC_2.14 GLIBC_2.4 GLIBC_2.11 GLIBC_2.2.5 GLIBC_2.3.4Also, check the higher versioning symbol of the libc:
readelf -V /lib64/libc.so.6
