pass_function.c

#include <stdio.h>
#include <string.h>

void report(int i)
{
    printf("[%s] %d\n", __FUNCTION__, i);
}

int main(void)
{
    char buf[32] = {0};
    
    report( snprintf(buf, sizeof(buf), "%d",123) );
    printf("len=%ld\n", strlen(buf));

    report( snprintf(buf, sizeof(buf), "%f",123.456) );
    printf("len=%ld\n", strlen(buf));

    /* Output
        [report] 3
        len=3
        [report] 10
        len=10
     */

    return 0;
}