question about using gcc and ld

[Min-Hua Chen <orca dot chen at gmail dot com>]

hi:

I tried to generate a binary executable by gcc and ld, but I had some problems.

1) I wrote a simple program, say test.c.

int main() { return 0;}

2) I compiled it by gcc:
%gcc -o a.out test.c

and I got a executable file a.out,
but when I tried to do the same thing by ld, there are some problems

%gcc -c a.c -o a.o
%ld -e main a.o -o b.out

I got b.out, a binary executable file, but when I executed b.out, I always got
segmentation fault.

I checked a.out and b.out with ldd
%ldd a.out

    linux-gate.so.1 =>  (0xffffe000)
    libc.so.6 => /lib/libc.so.6 (0xb7e31000)
    /lib/ld-linux.so.2 (0xb7f81000)

%ldd b.out
   noting

I don't understand why this happened. gcc calls ld to link object
file, but why can't I
generate the same result by using gcc and ld separately?
(the default linker script should work, does it?)

thx for reading
Min-Hua