how_many_forks.md

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How Many Forks Will Be Invoked in The following Code?

#include <stdlib.h>
int main(void) {
	system("bash -c pidof");
	return 0;
}

Figuring it out by using strace

strace -f <prog>

Figuring it out by useing perf

sudo perf record -e 'syscalls:sys_enter_*' -e 'sched:sched_*' <prog> sudo perf script

sudo perf record -e 'sched:sched_process_fork' -a sudo perf script

sudo perf record -e 'sched:sched_process_fork' -e 'sched:sched_process_exec' -a sudo perf script

Answer

It only fork once, which is called by system(3).

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