wait(&status) always return 0 - c

Question

I'm try to get exit status of child process but always gets 0.
what I'm doing wrong, is this not the way?
here is my code, tokens = an commands array.
thanks
int execute(char** tokens)
{
pid_t pid;
int status;
pid = fork();
if (pid == -1)
{
fprintf(stderr,"ERROR: forking child process failed\n");
return -1;
}
// Child process
if (pid == 0)
{
// Command was failed
if (execvp(*tokens, tokens) == -1)
{
fprintf(stderr, "%s:command not found\n", *tokens);
return 255;
}
}
else
{
pid = wait(&status);
status = WEXITSTATUS(status);
}
return status;
}
always:
status = 0.
what I need to change?

Answer 1

You'd probably want to exit(255) right away to ensure that the correct status is returned. Also wait is very probable to get EINTR. Also, the return status is meaningful only if WIFEXITED(status), otherwise you shouldn't rely on it:
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <errno.h>
int execute(char** tokens)
{
pid_t pid;
int status;
pid = fork();
if (pid == -1)
{
fprintf(stderr,"ERROR: forking child process failed\n");
return -1;
}
// Child process
if (pid == 0)
{
// Command was failed
if (execvp(*tokens, tokens) == -1)
{
fprintf(stderr, "%s: command not found\n", *tokens);
exit(255);
}
}
else {
while (1) {
pid = wait(&status);
if (pid == -1) {
if (errno == EINTR) {
continue;
}
perror("wait");
exit(1);
}
break;
}
if (WIFEXITED(status)) {
int exitcode = WEXITSTATUS(status);
printf("%d\n", exitcode);
}
else {
printf("Abnormal program termination");
}
}
return status;
}
int main() {
char *args[] = {
"/bin/cmd_not_found",
"Hello",
"World!",
0
};
execute(args);
}