ZSH wait() syscall test bench for #BashOnUbuntuOnWindows. See https://github.com/Microsoft/BashOnWindows/issues/91#issuecomment-208077623

main.c

#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/wait.h>
#include <stdio.h>
#include <errno.h>


int main() {
    pid_t pid;
    int status;

#define WAITFLAGS (WNOHANG|WUNTRACED|WCONTINUED)

#ifdef HAVE_WAIT3
# ifdef HAVE_GETRUSAGE
    struct rusage ru;
    pid = wait3((void *)&status, WAITFLAGS, &ru);
# else
    pid = wait3((void *)&status, WAITFLAGS, NULL);
# endif
#else
# ifdef HAVE_WAITPID
    pid = waitpid(-1, &status, WAITFLAGS);
# else
    pid = wait(&status);
# endif
#endif

    if (pid == -1) {
        if (errno != ECHILD) {
            perror("wait failed");
            return errno;
        }
    }

    return 0;
}

Makefile

.PHONY: all test clean

.IGNORE: test

all: wait3_getrusage wait3 waitpid wait

wait3_getrusage: main.c
	gcc main.c -D HAVE_WAIT3 -D HAVE_GETRUSAGE -o wait3_getrusage

wait3: main.c
	gcc main.c -D HAVE_WAIT3 -o wait3

waitpid: main.c
	gcc main.c -D HAVE_WAITPID -o waitpid

wait: main.c
	gcc main.c -o wait

test: wait3_getrusage wait3 waitpid wait
	./wait3_getrusage
	./wait3
	./waitpid
	./wait

clean: wait3_getrusage wait3 waitpid wait
	rm -rf wait3_getrusage wait3 waitpid wait