debug a multi process in gdb?

by zhou jianxi » Tue, 01 May 2001 17:08:23

Hi all:

......
if((pid = fork()<0)
{
printf("fork error!.\n");
exit(-1);
}
A: printf("pid=%d.\n",pid);
if(pid>0){...........}
if(pid<0){............}

when I debug it in gdb,set breakpoint at A,then run;after it print the value
of pid,the pid is larger 0(assume it is 1001),so it is the child process's
ID;
I have thought the pid should be 0 after I do :
gdb>attach 1001
but the pid was not changed.
what is wrong.
can anybody give help for me?
thx !

regards
zhou

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1. Problems with debugging multi-threaded application with gdb

Hello,

I have problems with debugging multi-threaded application wtih dbg. The
below program runs perfectly without gdb. Under gdb (no breakpoints set) the
program terminates in either of the two assert() statements. I'm desperately
looking for the answer why.

Thanks,
Slawek

#include <stdio.h>
#include <unistd.h>
#include <pthread.h>
#include <assert.h>

void *
thread_routine(void *a)
{
unsigned int ret;

printf("Started\n");

ret = sleep(5);
assert(ret == 0); /* !!!!!!!!!!!!!!!!!!!! HERE (ret is equal 5)
!!!!!!!!!!!!!!!!!!!!!!! */

printf("Stopped\n");

return NULL;

int
main(void)
{
pthread_t pid;
int i;
int ret;

/* we start with default attributes ... */
for (i = 0; i < 10; i++)
pthread_create(&pid, NULL, thread_routine, NULL);

ret = sleep(10);
assert(ret == 0); /* !!!!!!!!!!!!!!!!!!!! HERE (ret is equal 10)
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! */

return 0;

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