Question

The GMP docs say that static linking may provide a small performance improvement.

I am having a problem getting it to staticly link libgmp on my Linux systems. I’ve narrowed down the issue I’m having to a tiny test case.

gmptest.c

#include <gmp.h>

int main(int argc, char** argv) {
    mpz_t foo;
    mpz_init(foo);
    return 0;
}

Makefile:

all: clean gmptest static

clean:
    rm -f *.s
    rm -f *.o
    rm -f gmptest
    rm -f static-gmptest

gmptest: Makefile gmptest.c
    gcc -std=c99 -O3 -lgmp gmptest.c -o gmptest

static: clean Makefile gmptest.c
    gcc -std=c99 -O3 -static /usr/lib/libgmp.a gmptest.c -o static-gmptest

The non-static binary is compiled and linked without any issues, but ‘Make static’ produces:

gcc -std=c99 -O3 -static /usr/lib/libgmp.a gmptest.c -o static-gmptest
/tmp/ccWSFke9.o: In function `main':
gmptest.c:(.text+0x8): undefined reference to `__gmpz_init'
collect2: ld returned 1 exit status
make: *** [static] Error 1

The library does exist:

chris@vostro:~/Dropbox/static$ ls -lA /usr/lib/libgmp.a 
-rw-r--r-- 1 root root 1041666 2010-02-26 13:20 /usr/lib/libgmp.a

I have also tried -lgmp for the static linking, but the error is the same.

This is all on Ubuntu 10.04 and 10.10 AMD64.

Can some enlighten me as to the obvious error I’m making?

Thanks,

Chris.

Answer 1

Try

 gcc -std=c99 -O3 -static gmptest.c -lgmp -o static-gmptest

since libraries should always be linked in the good order, and after the program or object files using them.