This is more of a curiosity thing than anything as I must admit, I don't know a whole lot of C.

Can someone explain what I'm missing in the below code? In the C num() function, I have a uint8_t argument, which causes an error:

Undefined subroutine &main::num called at perl.pl line 6.
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The broken code:

use warnings;
use strict;

use Inline 'C';

num(1);

__END__
__C__

#include <stdio.h>
#include <inttypes.h>

void num(uint8_t number){
    printf("%d\n", number);
}
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However, if I accept the argument as an int, and then cast it to uint8_t, it works fine:

void num(int number){
    number = (uint8_t)number;
    printf("%d\n", number);
}
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The code that breaks in Perl (uint8_t in the function definition) works fine when compiling/running it as a straight up C program.