CODEWITHSUNDEEP
cstring
payne
payne

Reputation: 5269

NUL-terminating a string by hand

Here is the method on my server-side: 

void send_err(int socket_fd, char *msg) {
    /// To send an error message (`ERR`).

    size_t len = strlen(msg);
    printf("send_err: msg='%s' of size:%zu\n", msg, len);


    INIT_HEAD_S(head_s, ERR, len);
    send_header(socket_fd, &head_s, sizeof(cmd_header_t));
    send_msg(socket_fd, msg, len * sizeof(char));
}

I call the method this way: send_err(socket_fd, "»»»»»»»»» illogical REQ request.\0");

The socket is set up properly, and the send_header and send_args methods work fine.

On the server-side, the printf works just fine, but the strlen does not return the proper value (it should be 33, but it's giving out 43 instead).

On the client-side, the message received is undefined: some times there are weird extra characters appearing. Apparently, manually adding a \0 doesn't seem to actually add a NUL character at the end of my String.

How am I supposed to do this? I want the method to not require the person to count how many characters they are sending since it's annoying to do so.

Upvotes: 4

Views: 84

Answers (1)

payne
payne

Reputation: 5269

void send_err(int socket_fd, char *msg) {
    /// To send an error message (`ERR`).

    size_t len = strlen(msg)+1; // because `strlen` doesn't include the NUL char
    printf("send_err: msg='%s' of size:%zu\n", msg, len);


    INIT_HEAD_S(head_s, ERR, len);
    send_header(socket_fd, &head_s, sizeof(cmd_header_t));
    send_msg(socket_fd, msg, len * sizeof(char));
}

As Alex F suggested in the comments, my error was with the manipulation of strlen. I simply needed to add a +1.

Upvotes: 4

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