gistfile1.cpp

#include <stdio.h>

int func(int v) {
    printf("%d\n", v);
    return 0;
}

void f1(unsigned char b, unsigned char c) {
    auto a = b + c;
    func(a);
    printf("%d\n", sizeof(a)); // 4
}

void f2(unsigned char b, unsigned char c)
{
    func(b + c);
}

int main()
{
    f1(1,255);
    f2(1,255);
}