©2004 by Marc J. Rochkind. All rights reserved. Portions marked "Open Source" may be copied under license.

 

                 

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c5/waitid.c

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/*
    waitid example
    AUP2, Sec. 5.08

    Copyright 2003 by Marc J. Rochkind. All rights reserved.
    May be copied only for purposes and under conditions described
    on the Web page www.basepath.com/aup/copyright.htm.

    The Example Files are provided "as is," without any warranty;
    without even the implied warranty of merchantability or fitness
    for a particular purpose. The author and his publisher are not
    responsible for any damages, direct or incidental, resulting
    from the use or non-use of these Example Files.

    The Example Files may contain defects, and some contain deliberate
    coding mistakes that were included for educational reasons.
    You are responsible for determining if and how the Example Files
    are to be used.

*/
#include "defs.h"

#if defined(_XOPEN_UNIX)

void display_status(siginfo_t *infop);

/*[waitid-wait_and_display]*/
static bool wait_and_display(void)
{
    siginfo_t info;

#if defined(LINUX) && !defined(WEXITED)
#define WEXITED 0
#endif
    ec_neg1( waitid(P_ALL, 0, &info, WEXITED) )
    display_status(&info);
    return true;

EC_CLEANUP_BGN
    return false;
EC_CLEANUP_END
}

void display_status(siginfo_t *infop)
{
    printf("Process %ld terminated:\n", (long)infop->si_pid);
    printf("\tcode =  %s\n",
      get_macrostr("sigchld-code", infop->si_code, NULL));
    if (infop->si_code == CLD_EXITED)
        printf("\texit value =  %d\n", infop->si_status);
    else
        printf("\tsignal = %s\n",
          get_macrostr("signal", infop->si_status, NULL));
}

/*[]*/
int main(void)
{
    pid_t pid;

    /* Case 1: Explicit call to _exit */
    if (fork() == 0) /* child */
        _exit(123);
    /* parent */
    ec_false( wait_and_display() )

    /* Case 2: Termination by kernel */
    if (fork() == 0) { /* child */
        int a, b = 0;

        a = 1 / b;
        _exit(EXIT_SUCCESS);
    }
    /* parent */
    ec_false( wait_and_display() )

    /* Case 3: External signal */
    if ((pid = fork()) == 0) { /* child */
        sleep(100);
        _exit(EXIT_SUCCESS);
    }
    /* parent */
    ec_neg1( kill(pid, SIGHUP) )
    ec_false( wait_and_display() )

    exit(EXIT_SUCCESS);

EC_CLEANUP_BGN
    exit(EXIT_FAILURE);
EC_CLEANUP_END
}

#else /* _XOPEN_UNIX */

int main(void)
{
    printf("waitid not implemented\n");
    exit(EXIT_FAILURE);
}

#endif /* _XOPEN_UNIX */

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