procexec/print_wait_status.c

This is procexec/print_wait_status.c (Listing 26-2, page 546), an example from the book, The Linux Programming Interface.

The source code file is copyright 2022, Michael Kerrisk, and is licensed under the GNU Lesser General Public License, version 3.

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  Cover of The Linux Programming Interface

Function list (Bold in this list means a function is not static)

/* print_wait_status.c

   Dissect and print the process termination status returned by wait()
   and related calls.
*/
#define _GNU_SOURCE     /* Get strsignal() declaration from <string.h> */
#include <string.h>
#include <sys/wait.h>
#include "print_wait_status.h"  /* Declaration of printWaitStatus() */
#include "tlpi_hdr.h"
/* NOTE: The following function employs printf(), which is not
   async-signal-safe (see Section 21.1.2). As such, this function is
   also not async-signal-safe (i.e., beware of calling it from a
   SIGCHLD handler). */

void                    /* Examine a wait() status using the W* macros */
printWaitStatus(const char *msg, int status)
{
    if (msg != NULL)
        printf("%s", msg);

    if (WIFEXITED(status)) {
        printf("child exited, status=%d\n", WEXITSTATUS(status));

    } else if (WIFSIGNALED(status)) {
        printf("child killed by signal %d (%s)",
                WTERMSIG(status), strsignal(WTERMSIG(status)));
#ifdef WCOREDUMP        /* Not in SUSv3, may be absent on some systems */
        if (WCOREDUMP(status))
            printf(" (core dumped)");
#endif
        printf("\n");

    } else if (WIFSTOPPED(status)) {
        printf("child stopped by signal %d (%s)\n",
                WSTOPSIG(status), strsignal(WSTOPSIG(status)));

#ifdef WIFCONTINUED     /* SUSv3 has this, but older Linux versions and
                           some other UNIX implementations don't */
    } else if (WIFCONTINUED(status)) {
        printf("child continued\n");
#endif

    } else {            /* Should never happen */
        printf("what happened to this child? (status=%x)\n",
                (unsigned int) status);
    }
}

 

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