Question

I have a Perl program and a C program. I want to run the Perl program and capture the return value of C program. To make it clear:

C program (a.out)

int main()
{
    printf("100");
    return 100;
}

Perl program:

print `ls`; #OK
print `a.out`; #No error but it does not print any output.

Any ideas?
Thanks.

Answer 1

I don’t know perl but this works on my system so no guarantees:

#!/usr/bin/perl

print "Running a.out now\n";
$exitCode = system("./a.out");
print "a.out returned:\n";
print $exitCode>>8; print "\n";

For one reason or another system() returns the return value bitshfted by 8 (so 0 will become 256, 1 will be 512… 7 will be 1792 or something like that) but I didn’t care to look up why.