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Expand upon the argument for

This commit is contained in:
Nick Chambers 2023-12-27 16:12:07 -06:00
parent 592ddbc2af
commit fb132a4f0f
1 changed files with 8 additions and 5 deletions
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13
exec.c
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@ -13,8 +13,8 @@ int main() {
pid_t pid = fork(); pid_t pid = fork();
// When the child process returns from `fork`, the value assigned to `pid` // When the child process returns from `fork`, the value assigned to `pid`
// will be 0. In the parent process, `pid` will be the process ID (PID) of the // will be 0. In the parent process, `pid` will be the process ID (a non-0
// child process. // number) of the child process.
if(pid == 0) { if(pid == 0) {
// This call to `exec` will only be run by the child process. This is // This call to `exec` will only be run by the child process. This is
// because `exec` replaces the process' instructions with the instructions // because `exec` replaces the process' instructions with the instructions
@ -26,10 +26,13 @@ int main() {
execvp(cmdline[0], cmdline); execvp(cmdline[0], cmdline);
} else { } else {
// In the parent process, pause until the child process exits. The `wait` // In the parent process, pause until the child process exits. The `wait`
// function takes a pointer to a structure that contains information about // function takes a pointer to an integer that contains information about
// how the child process exited. If the exit information isn't necessary, // how the child process exited. If the exit information isn't necessary,
// `NULL` can be passed instead. // `NULL` can be passed instead. Several macros are available to obtain
wait(NULL); // further information about how the process exited.
int status = 0;
wait(&status);
printf("Process %d exited with status %d.\n", pid, status);
} }
// The parent process is now finished, and will return the number `0` to // The parent process is now finished, and will return the number `0` to