ld does not link object file generated by as

Question

I have written a Hello World program in C. I used the command gcc -S -o hello.s hello.c (code was in hello.c) to generate assembly, then used as to assemble it. Finally I linked the object code using ld, but it gave me the following error:

ld: a.out:hello.c:(.text+0xa): undefined reference to `__main'
ld: a.out:hello.c:(.text+0x16): undefined reference to `puts'

The C code was as follows:

#include <stdio.h>
int main(void) {
    printf("Hello world!\n");
} 

I use an Intel Core i3 processor, and used MinGW to compile. My operating system is Windows 7.

This was the generated assembly:

    .file   "hello.c"
    .text
    .def    ___main;    .scl    2;  .type   32; .endef
    .section .rdata,"dr"
LC0:
    .ascii "Hello world!\0"
    .text
    .globl  _main
    .def    _main;  .scl    2;  .type   32; .endef
_main:
LFB13:
    .cfi_startproc
    pushl   %ebp
    .cfi_def_cfa_offset 8
    .cfi_offset 5, -8
    movl    %esp, %ebp
    .cfi_def_cfa_register 5
    andl    $-16, %esp
    subl    $16, %esp
    call    ___main
    movl    $LC0, (%esp)
    call    _puts
    movl    $0, %eax
    leave
    .cfi_restore 5
    .cfi_def_cfa 4, 4
    ret
    .cfi_endproc
LFE13:
    .ident  "GCC: (MinGW.org GCC Build-2) 9.2.0"
    .def    _puts;  .scl    2;  .type   32; .endef

Answer 1

Thanks to Nate Eldredge for helping me get the answer.

To link the file produced by as, use gcc -v (file).