John the ripper (external mode)i

John the ripper (external mode)i

I can't seem to get this to work?

[List.External:ConcatWords]
void init() {
    word[0] = 0;
}
void generate() {
    int i = 0;
    int len = 0;                                                               
 // Concatenate word1
    while (i < word1_len) {
        word[len++] = word1[i++];
    }                                                                           // Concatenate word2
    while (i < word2_len) {
        word[len++] = word2[i++];
    }
    // Concatenate word3 (if provided)
    if (word3_len > 0) {
        word[len++] = 32; // Add space separator
        while (i < word3_len) {
            word[len++] = word3[i++];
        }
    }                                                                           word[len] = 0;
}