Static Helper

A static helper function keeps implementation details private to one source file.

static_helper.c

#include <stdio.h>

static int clamp_to_limit(int value) {
    if (value > 10) {
        return 10;
    }
    return value;
}

int main(void) {
    int input = ;
    int clamped = clamp_to_limit(input);

    printf("clamped=%d\n", clamped);
    return 0;
}

#include <stdio.h>

static int clamp_to_limit(int value) {
    if (value > 10) {
        return 10;
    }
    return value;
}

int main(void) {
    int input = ;
    int clamped = clamp_to_limit(input);

    printf("clamped=%d\n", clamped);
    return 0;
}

#include <stdio.h>

static int clamp_to_limit(int value) {
    if (value > 10) {
        return 10;
    }
    return value;
}

int main(void) {
    int input = ;
    int clamped = clamp_to_limit(input);

    printf("clamped=%d\n", clamped);
    return 0;
}

internal linkage At file scope, `static` limits a helper function to the current translation unit.

small boundary The public code calls a named operation while the helper owns one detail.