Tukukkk

I have the task that the parent process needs to output exit code of the child process. This exit code is supposed to be the sum of the child process id, with an added variable k and modulo 100 of the whole. I have tried two approaches to save the exit-code from the child process:

• exit(exit-code) in child process and saving in parent process with wait(). You should still this in the comments


• saving exit-code in global variable and outputting exit-code after wait() in parent process

However, both did not work. Could you help me how I could achieve it? Thank you!

#include <stdio.h>

#include <stdlib.h>

#include <sys/types.h>

#include <sys/wait.h>

#include <unistd.h>

#include <string.h>

#include <time.h>



//globale Variable

int out;



int main()

{

//Nutzereingabe von k:

int k=0;

scanf("%d",&k);

    //Erzeugen eines Kindprozesses:

    if(fork()==0)

    {

        //Kindprozess liegt vor

    int zaehler=1;

    char ausgabe[256]={0};

    while(zaehler<=k){

        //printf("%dt"

        int pid=getpid();

        int ppid=getppid();

        sprintf(ausgabe, "%d %c %d %c %dn", pid,' ', ppid,' ',zaehler);

        write(STDOUT_FILENO, ausgabe, strlen(ausgabe));

        sleep(1);

    zaehler++;

    }   

    //write(STDOUT_FILENO, (getpid()+k)%100, strlen((getpid()+k)/100));

    //printf("%dn", (getpid()+k)%100);

    out=(getpid()+k)%100;

    printf("%i", out);

    exit((getpid()+k)%100);

 }

    else

    {

        //Elternprozess liegt vor

        time_t curtime;

        time(&curtime);

        printf("Start: %s", ctime(&curtime));



    }

    //int exitcode=wait(NULL);

    wait(NULL);

    //exitcode to String casten:

    char str[24];

    sprintf(str, "Exit-Code: %in", out);

    //Ausgabe und exitcode zu einem String zusammenfuegen: (vorher concat())

    //char* s = concat("Exit-Code: ", str);

    //strncat(*str,"Exit-Code: ",str);

    //Ausgabe des Exitcodes:

    write(STDOUT_FILENO, str, strlen(str));

    time_t curtime;

    time(&curtime);

    printf("Ende: %sn", ctime(&curtime));

    return 0;

}

From man wait:

pid_t wait(int *status);

If status is not NULL, wait() and waitpid() store status information in the int to which it points.

WEXITSTATUS(status)
returns the exit status of the child. This consists of the least significant 8 bits of the status argument that the child specified in a call to exit(3) or _exit(2) ....

So use:

}

// warte fur unserer kind

int exitstatus;

wait(&exitstatus);

// caste exitcode to string casten

char str[24];

sprintf(str, "Exit-Code: %dn", WEXITSTATUS(exitstatus));