where is the string literal allocated ? On the stack ?

[Brian Dessent]

Michael Gong wrote:

> Though it's not related with gcc, could anyone help me with following
> question:
> 
> Where is the string literal allocated ? Is it on the stack ?
> 
> For example, where is "abc" allocated ?
> 
> char * foo() {
>     return "abc";
> }

Everyone else has already answered your question directly, but I'd like
to point out that the compiler is not a black box -- you can easily see
exactly what it's doing with a few simple commands.  Check the docs for
on -S, -save-temps, -fverbose-asm, etc.  For example:

$ echo 'char * foo() { return "abc"; }' | gcc -x c - -S -o
-              
        .file   ""
        .section        .rodata
.LC0:
        .string "abc"
        .text
.globl foo
        .type   foo, @function
foo:
        pushl   %ebp
        movl    %esp, %ebp
        movl    $.LC0, %eax
        popl    %ebp
        ret
        .size   foo, .-foo
        .ident  "GCC: (GNU) 4.0.4 20060507 (prerelease) (Debian
4.0.3-3)"
        .section        .note.GNU-stack,"",@progbits

As you can see, it goes in the .rodata section.  The above is the
behavior under linux, but for PE (Win32) it is a different section:

$ echo 'char * foo() { return "abc"; }' | gcc -x c - -S -o -
        .file   ""
        .section .rdata,"dr"
LC0:
        .ascii "abc\0"
        .text
.globl _foo
        .def    _foo;   .scl    2;      .type   32;     .endef
_foo:
        pushl   %ebp
        movl    %esp, %ebp
        movl    $LC0, %eax
        popl    %ebp
        ret

That is my second point: this kind of thing is platform-dependant
(although it can never be on the stack), and you didn't mention at all
what platform you are using in your original question, which should be a
requirement for almost any compiler/toolchain question.

Brian