Named piped error - c

Question

Sorry for the poor title, i didnt' know how to explain this simply.
I have 2 programs : a server and a client.
Server make a named pipe and waits to read something. Client connects and send a message to the pipe. Server checks a part of the message to get the "type" of the message (in this case, type is "HELO") reading char 4 to 8 of the sent string. If i send "HELO", server prints "Type : HELO" as expected.
But if i send a message with something else, it doesn't print "No match" as expected : it just does nothing.
Here is the code :
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#define BUF_SIZE 256
char * getType(char * message){
char* type = malloc(sizeof(char)*5);
memcpy(type,&message[4],4);
type[4] = '\0';
return type;
}
int main(int argc, char* argv[]){
mkfifo("tchatserv", 0666);
int fd = open("tchatserv", O_RDONLY);
char buf[BUF_SIZE];
int val;
while(1){
val = read(fd, buf , BUF_SIZE );
if(val >0){
char * type = getType(buf);
if(strcmp("HELO",type) == 0){
printf("Type: %s\n", type);
}
else{
printf("no match");
}
}
}
}
Here is client :
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#include <fcntl.h>
char * makeInt(int val){
char* res = malloc(sizeof(char)*5);
char l [5] = "";
sprintf(l,"%d",val);
if(val < 10){
strcat(res,"000");
strcat(res,l);
}
else if(val < 100){
strcat(res,"00");
strcat(res,l);
}
else if(val < 1000){
strcat(res,"0");
strcat(res,l);
}
else if( val < 10000){
strcat(res,l);
}
return res;
}
char * makeString(char * ch, int final){
int t = strlen(ch);
if(final == 1){
t = t+4;
}
char * chaine = makeInt(t);
strcat(chaine,ch);
return chaine;
}
void connection(){
printf("Pseudo:\n");
char * pseudo = malloc(sizeof(char)*30);
pseudo[0] = '\0';
scanf("%s", pseudo);
printf("Tube:\n");
char * tube = malloc(sizeof(char)*30);
tube[0] = '\0';
scanf("%s", tube);
char * message = malloc(sizeof(char)*100);
char * type = "HELO";
message[0] = '\0';
strcat(message,type);
pseudo = makeString(pseudo,0);
strcat(message,pseudo);
tube = makeString(tube,0);
strcat(message,tube);
message = makeString(message,1);
printf("%s",message);
int fd = open("tchatserv", O_WRONLY);
write(fd,message,256);
}
int main(int argc, char* argv[]){
connection();
return 0;
}
EDIT: When i try to send something else than HELO it doesn't print "no match" but then i send HELO and it prints : "no match Type: HELO", like if the first "no match" got stuck in the pipe instead of getting printed immediately, i don't understand why.

Answer 1

When i try to send something else than HELO it doesn't print "no match" but then i send HELO and it prints : "no match Type: HELO", like if the first "no match" got stuck in the pipe instead of getting printed immediately, i don't understand why.
The no match indeed got stuck in a way, though not in the pipe, but rather in the server's buffer of the standard output stream, which is presumably line buffered, i. e., characters are transmitted (printed) when a new-line is encountered. To cure this, just change the printf("no match") to printf("no match\n") or puts("no match").