39 lines
972 B
C
39 lines
972 B
C
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// demonstrate non-blocking waitpid() in excess
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/wait.h>
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#include <unistd.h>
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int main(int argc, char* argv){
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char *child_argv[] = {"./complain",NULL};
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char *child_cmd = "complain";
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printf("PARENT: Junior is about to '%s', I'll keep an eye on him\n",
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child_cmd);
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pid_t child_pid = fork();
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// CHILD CODE
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if(child_pid == 0){
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printf("CHILD: I'm %d and I'm about to '%s'\n",
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getpid(), child_cmd);
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execvp(child_cmd, child_argv);
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}
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// PARENT CODE
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int status;
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int checked = 0;
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while(1){
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int cpid = waitpid(child_pid,&status,WNOHANG); // Check if child done, but don't actually wait
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if(cpid == child_pid){ // Child did finish
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break;
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}
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printf("Oh, junior's taking so long. Is he among the 50%% of people that are below average?\n");
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checked++;
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}
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printf("PARENT: Good job junior. I only checked on you %d times.\n",checked);
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return 0;
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}
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