how to linking with dynamic lib (.so) and static libc.a

Question

I'm trying to link with the static libc.a and a dynamic lib .so unsuccessfully.

I've already tryied the following:

1. Firstly I test with all dynamic:

   • gcc -shared libtest.c -o libtest.so
   • gcc -c main.c -o main.o
   • gcc main.o -o test -L. -ltest

   It's working (compile and execute)

2. Secondly I test what I want (dynamic lib and static libc) :

   • gcc -shared libtest.c -o libtest.so
   • gcc -c main.c -o main.o
   • gcc main.o -o test libtest.so /usr/lib/libc.a

   It's compiling, but at execution, it segfault! A strace show that it's trying to access libc.so!!!

3. Finally I've tried to compile a simple progam with no reference to dynamic lib

   • gcc -static main.c --> compile ok, run ok
   • gcc main.c /usr/lib/libc.a --> compile ok, run : segmentation fault (a strace show that it's access to libc.so)

How to do that?

Thank you

Solution

Your second test (the one you want to do) is working for me on i686-linux:

$ cat libtest.c 
#include <stdio.h>
void foo() { printf("%d\n", 42); }
$ cat main.c
#include <stdio.h>
extern void foo();
int main() { puts("The answer is:"); foo(); }
$ export LD_LIBRARY_PATH=$PWD                                                                                              
$ gcc -shared libtest.c -o libtest.so && gcc -c main.c -o main.o && gcc main.o -o test -L. -ltest && ./test        
The answer is:
42
$ gcc -shared libtest.c -o libtest.so && gcc -c main.c -o main.o && gcc main.o -o test libtest.so /usr/lib/libc.a && ./test
The answer is:
42

However, you have to realise that the shared library you've build depends on the shared libc. So, it's natural that it's trying to open it at runtime.

$ ldd ./libtest.so 
    linux-gate.so.1 =>  (0xb80c7000)
    libc.so.6 => /lib/i686/cmov/libc.so.6 (0xb7f4f000)
    /lib/ld-linux.so.2 (0xb80c8000)

One way to achieve what you want is to use: -static-libgcc -Wl,-Bstatic -lc.