Safe concatenating of strings in C

string_concatenate.c

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

void safeConcatenate(char *buffer, int size, char *string1, char *string2);

int main(int argc, char *argv[]) {
    char buffer[1024] = {0};
    char *string1 = "foo";
    char *string2 = "bar";

    safeConcatenate(buffer, 1024, string1, string2);
    printf("Concatenated string: %s\n", buffer);
}

void safeConcatenate(char *buffer, int size, char *string1, char *string2) {
    if (strlen(string1) + strlen(string2) > size) {
        printf("Bufferoverflow!");
        exit(1);
    } else {
        strcat(buffer, string1);
        strcat(buffer, string2);
    }
}