From: "Jonathan A. George" <JAGeorge@greshamstorage.com>
To: linux-kernel@vger.kernel.org
Subject: Help? 2.4 to 2.6 pthread problem with popen in gdb
Date: Mon, 10 May 2004 17:37:32 -0500 [thread overview]
Message-ID: <40A0042C.6000603@greshamstorage.com> (raw)
Is there a work around for the wait4 failure in gdb when debugging a
program that uses popen from within a pthread?
The behavior is:
correct 2.4
correct 2.4 in gdb 6.x
correct 2.6
failure 2.6 gdb 6.x
Even the most trivial program which uses popen from within a pthread
will fail immediately, but ONLY under 2.6 and ONLY gdb. This problem
has manifested from 2.6.0 - 2.6.6 in the vanilla mainline kernels using
the current libc/pthread/gdb/gcc from Debian Sid tested with each tool
or kernel update.
--Jonathan--
P.S. Example code below compiles with g++ filename.cpp -lpthread
#include <iostream>
using namespace std;
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
void *
thread_start( void *thread_arg )
{
cout << "arg=" << (long) thread_arg << endl;
FILE *popen_file = popen( "ping -c3 127.0.0.1", "r" );
cout << "errno=" << errno << endl;
if( popen_file )
{
char linebuf[ 0xff ];
char *fgets_result = NULL;
while( NULL != (fgets_result =
fgets( linebuf, sizeof( linebuf ), popen_file )) )
{
cout << "fgets_result=" << fgets_result;//<< endl;
}
int pclose_result = pclose( popen_file );
cout << "pclose_result=" << pclose_result << endl;
}
return( NULL );
}
int
main()
{
cout << "hello world" << endl;
pthread_t tid = 0;
pthread_attr_t pattr;
pthread_attr_init( &pattr );
pthread_attr_setdetachstate(
&pattr, PTHREAD_CREATE_DETACHED );
pthread_create(
&tid, &pattr, thread_start, (void *) 12345L );
//pthread_join( tid, NULL );
cout << "sleeping" << endl;
sleep( 20 );
return( 0 );
};
reply other threads:[~2004-05-10 22:43 UTC|newest]
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