C standard library and object files - c

Question

I know that every header file, i.e. string.h, should have an object file in which
there is the proper implementation.
I also know that for GCC and glibc there is a libc.a or libc.so containing object files.
I tried to open libc.a to see if I could find, i.e., string.o but I didn't find it.
Why? Where can I find for every header the correspondent object file?

Answer 1

It may be implementation dependant. A single .h file may correspond to many .o or the opposite, you might have many .h for a single .o
For example, in my libc.a, I can see about one module per string function :
$ ar t libc.a | grep '^str' | sort
strcasecmp.o
strcasestr.o
strcat.o
strchr.o
strcmp.o
strcoll.o
strcpy.o
strcspn.o
strdup.o
strerror.o
strfmon.o
strftime.o
stringlist.o
strlcat.o
strlcpy.o
strlen.o
strmode.o
strncat.o
strncmp.o
strncpy.o
strndup.o
strnlen.o
strnstr.o
strpbrk.o
strptime.o
strrchr.o
strsep.o
strsignal.o
strspn.o
strstr.o
strtofflags.o
strtoimax.o
strtok.o
strtol.o
strtoll.o
strtonum.o
strtoq.o
strtoul.o
strtoull.o
strtoumax.o
strtouq.o
strxfrm.o

Answer 2

well, in my system, libc.so shows up in /lib
[sourav#braodsword temp]$ ls -l /lib/libc*
-rwxr-xr-x 1 root root 1611564 Mar 10 2010 /lib/libc-2.5.so
However, if you're looking for the source code, you'll not find that in .so file, anyway.
Again, don't expect, every header file declaration will have a defferent object file. They are taken together to form the shared library .so.