compiler destroys terminal

This is a discussion on compiler destroys terminal within the C Programming forums, part of the General Programming Boards category; Hi! I'm trying to compile a program in C, but when I run it the terminal goes nuts and looks ...

  1. #1
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    1

    Question compiler destroys terminal

    Hi!

    I'm trying to compile a program in C, but when I run it the terminal goes nuts and looks like this:
    Code:
    ├┤␍␊┼├@⎽▒┼┼├␋␍⎽⎻␌:·/⎽▒┼┼⎻⎼⎺±01/␤␋␤␋/⎻⎼⎺⎽┘␊┐├/␤␊␋⎽$
    I'm compiling it with "gcc -lpthread -o server server.c" and the code I'm compiling follows beneath my name. I'm posting the whole thing since I can't read what the error may be. Can anyone see what's wrong? :|

    Harald

    Code:
    /* Creates a datagram server.  The port 
       number is passed as an argument.  This
       server runs forever */
    
    #include <sys/types.h>
    #include <sys/socket.h>
    #include <netinet/in.h>
    #include <netdb.h>
    #include <stdio.h>
    #include <pthread.h>
    #include <stdlib.h>
    #include <unistd.h>
    #include <errno.h>
    #include <string.h>
    #include <arpa/inet.h>
    
    #define BROADCASTPORT 9856    // the port users will be connecting to
    
    void error(char *msg)
    {
        perror(msg);
        exit(0);
    }
    
    /* Broadcasting all info to the network */
    int server_broadcast()
    {
       int sock, length, fromlen, n;
       struct sockaddr_in server;
       struct sockaddr_in from;
       char buf[1024];
    	int broadcast = 1;
    	
       sock=socket(AF_INET, SOCK_DGRAM, 0);
       if (sock < 0) error("Opening socket");
          
       if (setsockopt(sock, SOL_SOCKET, SO_BROADCAST, &broadcast,
           sizeof(broadcast)) == -1) {
           perror("setsockopt (SO_BROADCAST)");
           exit(1);
       }   
        
       length = sizeof(server);
       bzero(&server,length);
       server.sin_family=AF_INET;
       server.sin_addr.s_addr=INADDR_ANY;
       server.sin_port=htons(BROADCASTPORT);
       if (bind(sock,(struct sockaddr *)&server,length)<0) 
           error("binding");
       fromlen = sizeof(struct sockaddr_in);
       while (1) {
           write(1,buf,n);
           n = sendto(sock,"Broadcast message\n",19, 0,(struct sockaddr *)&from,fromlen);
           if (n  < 0) error("sendto");
       }
    }
    
    /* Listener for incoming datagrams from clients */
    int client_listener()
    {
       int sock, length, fromlen, n;
       struct sockaddr_in server;
       struct sockaddr_in from;
       char buf[1024];
    
      
       sock=socket(AF_INET, SOCK_DGRAM, 0);
       if (sock < 0) error("Opening socket");
       length = sizeof(server);
       bzero(&server,length);
       server.sin_family=AF_INET;
       server.sin_addr.s_addr=INADDR_ANY;
       server.sin_port=htons(BROADCASTPORT);
       if (bind(sock,(struct sockaddr *)&server,length)<0) 
           error("binding");
       fromlen = sizeof(struct sockaddr_in);
       while (1) {
           n = recvfrom(sock,buf,1024,0,(struct sockaddr *)&from,&fromlen);
           if (n < 0) error("recvfrom");
           write(1,"Received a datagram: ",21);
           write(1,buf,n);
           n = sendto(sock,"Got your message\n",17, 0,(struct sockaddr *)&from,fromlen);
           if (n        < 0) error("sendto");
       }
     }
     
    int main(int argc, char *argv[])
    {
    	pthread_t thread1, thread2;
    	int nr1, nr2, var;
    	
    	nr1 = pthread_create(&thread1,NULL, (void *)server_broadcast, NULL);
    	/* nr2 = pthread_create(&thread2,NULL, (void *)client_listener, (void*) port);	*/
    
    	pthread_exit(NULL);	
    }

  2. #2
    ATH0 quzah's Avatar
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    The compiler isn't doing anything to your terminal. Your crappy program is. Man I hate sensationalists.


    Quzah.
    Hope is the first step on the road to disappointment.

  3. #3
    Mad OnionKnight's Avatar
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    Umeć, Sweden
    Posts
    555
    Something is printed. That means you can find your problem by tracing it backwards starting from the function calls that output stuff.
    Also, use STDOUT_FILENO instead of 1 in your write() calls.

  4. #4
    and the hat of wrongness Salem's Avatar
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    The edge of the known universe
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    > write(1,buf,n);
    Both buf and n contain garbage at this point in the progrm.

    Also, try to do this without using threads, it only makes it way more complicated than it needs to be.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

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