Thread: Garbage appearing

Hey guys,
I'm sending a phrase through a named pipe and my server receives it well but when printing the phrase he prints it well but then prints some garbage aswell

This is my client :

Code:

#include <sys/types.h>#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>


#define MAX_LINE 80


int main(int argc, char** argv) {
	char line[MAX_LINE];
	if(argc < 2) printf("Invocação do programa cliente mal realizada!\n");
	else if(strncmp(argv[1],"add",strlen(argv[1]))==0)
 	 	{
 		  	if(argc != 2) printf("O comando add foi mal invocado.\n Exemplo: ./cliente add n");
   		  	else
   		 	{	int pipe = open("trabfifo", O_WRONLY);
    				// get a line to send
				printf("Enter line: ");
				fgets(line, MAX_LINE, stdin);
				line[strlen(line)-1] = '\0';	
				// actually write out the data and close the pipe
				write(pipe, line, strlen(line));
   		 	}
		}	  
		else if(strncmp(argv[1],"help",strlen(argv[1])) == 0)
  		{	
  			ajuda();  		
  		} 	
  		else printf("Comando Inexistente.\n");
		return 1;
}

And now my server code :

Code:

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>


#define MAX_LINE 80


int main(int argc, char** argv) {
   int pipe;
   int n;
   char line[MAX_LINE];
   mkfifo("trabfifo",0646);


   // abrir um named pipe
   pipe = open("trabfifo", O_RDONLY);
   // ler a informação e fechar o pipe
   n = read(pipe, line, strlen(line));
   printf("%s \n",line);
   printf("%d \n",n);
   close(pipe);
   return 0;
}

After sending the phrase 'ola' the result is the following :

ola
�
4

Why is that garbage appearing in the mid ?

Thanks.

Originally Posted by stahta01

Note: I have never used pipe functions; my answer is a good guess on the problem.

Old code

Code:

char line[MAX_LINE];

Code:

n = read(pipe, line, strlen(line));

The changes I suggest

Code:

char line[MAX_LINE+1]={0};

Code:

n = read(pipe, line, MAX_LINE);

Tim S.

Changed it and worked.
Thanks very much Tim!

Well I know the read function just buffers whatever is actually there, where it's reading from. Unless your data has terminated strings, you will need to terminate them yourself.