Функция переводит на новую строку

struct PACKET {
    char option[OPTLEN]; // instruction
    char alias[ALIASLEN]; // client's alias
    char buff[BUFFSIZE]; // payload
}
...
//считываем temp, считывыем message
sendtoalias(&me, temp, message);
...

void sendtoalias(struct USER *me, char *target, char *msg) {
    int sent, targetlen;
    struct PACKET packet;
    
    if(target == NULL) {
        return;
    }
    
    if(msg == NULL) {
        return;
    }
    
    if(!isconnected) {
        fprintf(stderr, "You are not connected...\n");
        return;
    }
    msg[BUFFSIZE] = 0;
    targetlen = strlen(target);
    
    memset(&packet, 0, sizeof(struct PACKET));
    strcpy(packet.option, "whisp");
    strcpy(packet.alias, me->alias);
    strcpy(packet.buff, target);
    strcpy(&packet.buff[targetlen], " ");
    strcpy(&packet.buff[targetlen+1], msg);
    
    /* send request to close this connetion */
    sent = send(sockfd, (void *)&packet, sizeof(struct PACKET), 0);
}

strcpy(packet.buff, target); 
strcat(packet.buff," "); 
strcat(packet.buff, msg);