[vlc-devel] Re: can't call fork() in vlc.c

Sooyoung Sung maximus at cmu.edu
Tue Apr 6 18:14:22 CEST 2004


Hi,
here is a copy of the code.
Basically, I am trying to fork an application which grabs stream from a
stream server and feeds it into VLC.

Thanks.


/*****************************************************************************
 * vlc.c: the vlc player
 *****************************************************************************
 * Copyright (C) 1998-2004 VideoLAN
 * $Id: vlc.c,v 1.21 2004/01/25 17:16:05 zorglub Exp $
 *
 * Authors: Vincent Seguin <seguin at via.ecp.fr>
 *          Samuel Hocevar <sam at zoy.org>
 *          Gildas Bazin <gbazin at netcourrier.com>
 *          Lots of other people, see the libvlc AUTHORS file
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
 *****************************************************************************/

#include "config.h"

#include <stdio.h>                                              /*
fprintf() */
#include <stdlib.h>                                  /* putenv(),
strtol(),  */
#ifdef HAVE_SIGNAL_H
#   include <signal.h>                            /* SIGHUP, SIGINT,
SIGKILL */
#endif
#ifdef HAVE_TIME_H
#   include <time.h>                                               /*
time() */
#endif

#include <vlc/vlc.h>
#include <sys/types.h>
#include <unistd.h>

/*****************************************************************************
 * Local prototypes.
 *****************************************************************************/
#ifndef WIN32
static void SigHandler  ( int i_signal );
#endif

/*****************************************************************************
 * main: parse command line, start interface and spawn threads
 *****************************************************************************/
int main( int i_argc, char *ppsz_argv[] )
{
    int i_ret;

    fprintf( stderr, "VLC media player %s\n", VLC_Version() );

#ifdef HAVE_PUTENV
#   ifdef DEBUG
    /* Activate malloc checking routines to detect heap corruptions. */
    putenv( "MALLOC_CHECK_=2" );

    /* Disable the ugly Gnome crash dialog so that we properly segfault */
    putenv( "GNOME_DISABLE_CRASH_DIALOG=1" );
#   endif

    /* If the user isn't using VLC_VERBOSE, set it to 0 by default */
    if( getenv( "VLC_VERBOSE" ) == NULL )
    {
        putenv( "VLC_VERBOSE=0" );
    }
#endif

    int esmproxy_pid;
    if (!(esmproxy_pid=fork()))
    {
      const char *filename = "C:/PROGRA~1/CMU/ESM/proxy";
      const char *params[1] = {"-uid 4 -eid 207 -a 9821 -v 2 -S 1200 -P
9800 -p 9800 -Q 9810 -T tcp -w 65535 -M BW_LATENCY -logdir
/usr3/demo/2004.03.19.10.59.05.tcp.420.WEB_HOSTSET.BW_LATENCY_
RTT.51.228.0.0.AIAD.Multiple.Priority -ResourceRate Multiple
-ResourceAllocate Priority -l 420 -u AIAD:3000:100 -j 0 -i 0 -y
23450:20+23452:100+23454:300 -x 23650:23652 -e 128.2.220.47:982 3 -e
128.2.220.47:9824 -e 128.2.220.47:9825 -n 9820 -O 128.2.220.121 -o
9811 -B RTT -Y 127.0.0.1 -m 128.2.220.43 -A 128.2.220.43 -C
128.2.220.43 -q 0 -U sooyoungtest.11.00.02.on.log"};

      execvp(filename, params);
      exit(0);
    }

    /* Create a libvlc structure */
    i_ret = VLC_Create();
    if( i_ret < 0 )
    {
        return i_ret;
    }

#ifndef WIN32
    /* Set the signal handlers. SIGTERM is not intercepted, because we
need at
     * least one method to kill the program when all other methods failed,
and
     * when we don't want to use SIGKILL.
     * Note that we set the signals after the vlc_create call. */
    signal( SIGINT,  SigHandler );
    signal( SIGHUP,  SigHandler );
    signal( SIGQUIT, SigHandler );

    /* Other signals */
    signal( SIGALRM, SIG_IGN );
    signal( SIGPIPE, SIG_IGN );
#endif

    /* Initialize libvlc */
    i_ret = VLC_Init( 0, i_argc, ppsz_argv );
    if( i_ret < 0 )
    {
        VLC_Destroy( 0 );
        return i_ret;
    }

    /* Run libvlc, in non-blocking mode */
    i_ret = VLC_Play( 0 );

    /* Add a blocking interface and keep the return value */
    i_ret = VLC_AddIntf( 0, NULL, VLC_TRUE );

    /* Finish the threads */
    VLC_Stop( 0 );

    /* Destroy the libvlc structure */
    VLC_Destroy( 0 );

    return i_ret;
}

#ifndef WIN32
/*****************************************************************************
 * SigHandler: system signal handler
 *****************************************************************************
 * This function is called when a fatal signal is received by the program.
 * It tries to end the program in a clean way.
 *****************************************************************************/
static void SigHandler( int i_signal )
{
    static time_t abort_time = 0;
    static volatile vlc_bool_t b_die = VLC_FALSE;

    /* Once a signal has been trapped, the termination sequence will be
     * armed and subsequent signals will be ignored to avoid sending signals
     * to a libvlc structure having been destroyed */

    if( !b_die )
    {
        b_die = VLC_TRUE;
        abort_time = time( NULL );

        fprintf( stderr, "signal %d received, terminating vlc - do it "
                         "again in case it gets stuck\n", i_signal );

        /* Acknowledge the signal received */
        VLC_Die( 0 );
    }
    else if( time( NULL ) > abort_time + 2 )
    {
        /* If user asks again 1 or 2 seconds later, die badly */
        signal( SIGINT,  SIG_DFL );
        signal( SIGHUP,  SIG_DFL );
        signal( SIGQUIT, SIG_DFL );
        signal( SIGALRM, SIG_DFL );
        signal( SIGPIPE, SIG_DFL );

        fprintf( stderr, "user insisted too much, dying badly\n" );

        abort();
    }
}
#endif


> Sooyoung Sung wrote:
>> I tried calling fork() inside main() in vlc.c, but the compiler keeps
>> complaining "undefined reference to '_fork'.
>>
>
> Please send the code which you are trying (only vlc.c) then someone
> could probably figure out what you are doing wrong.
>
>> I included <unistd.h> and <sys/types.h>.
>> Call to 'execvp()' works fine, which puzzles me more. Any idea?
>
>
> --
> Kind greetings,
>
> Jean-Paul Saman
>
>
>
> --
> This is the vlc-devel mailing-list, see http://www.videolan.org/vlc/
> To unsubscribe, please read http://developers.videolan.org/lists.html
> If you are in trouble, please contact <postmaster at videolan.org>
>
>
>

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