How to get the exit code of program invoked by system call?
c++
Solution
Quoting `man system`:
The value returned is -1 on error (e.g. fork(2) failed), and the
return status of the command otherwise. This latter return status is
in the format specified in wait(2). Thus, the exit code of the command
will be WEXITSTATUS(status). In case /bin/sh could not be executed,
the exit status will be that of a command that does exit(127).
You need to use `WEXITSTATUS` to determine the exit code of the command. Your `b.c` needs to look something like:
#include <stdio.h>
#include <sys/wait.h>
int main()
{
int ret = system("./a.out");
if (WEXITSTATUS(ret) == 0x10)
return 0;
else
return 1;
}
Problem
For example, Program a.out: ``` int main() { return 0x10; } ``` Program b.out: ``` int main() { if(system("./a.out") == 0x10) return 0; else return -1; } ``` According to cppreference, the return value of `system()` is implementation-dependent. Thus, the attempt of program b.out is obvious erroneous. In the case above, how can I get `0x10` instead of an undetermined value? If system call is not the right tool, what's the proper way to do this?