Intel汇编-系统调用返回值

# An example of getting a return value from a system call (系统调用返回值)
#
#
    .section .bss
.lcomm pid, 4
.lcomm uid, 4
.lcomm gid, 4

    .section .text
    .globl main
main:
    movl $20, %eax
    int $0x80
    movl %eax, pid

    movl $24, %eax
    int $0x80
    movl %eax, uid

    movl $47, %eax
    int $0x80
    movl %eax, gid

end:
    movl $1, %eax
    movl $0, %ebx
    int $0x80
# gcc -g -o 02 02-returnvalue.s -m32
#
#if 0
(gdb) b *end
Breakpoint 1 at 0x11c1: file 02-returnvalue.s, line 25.
(gdb) r
Starting program: /home/02

Breakpoint 1, end () at 02-returnvalue.s:25
25              movl $1, %eax
(gdb) x/d &pid
0x5655900c :       1681427
(gdb) x/d &uid
0x56559010 :       1015
(gdb) x/d &gid
0x56559014 :       1001

ps -e
    1681427 pts/7    00:00:00 02

id
    uid=1015(wang) gid=1001(camera) groups=1001(camera)

#endif