Thread: read string from socket

I hardly ever touch C so apologies if this is totally basic!

After reading data from a socket all I want to do is print the string to the screen.

I have this code, as part of a larger script:

Code:

void read_socket(int s) {
   int status;
   char result[1024];
   
   status = read(s,result,sizeof(result));
   
   if ( status < 0 ) {
      fprintf(stderr,"Error reading from socket.");
      exit(0);
   }
   
   printf("string: %s\nbytes: %d\n", result, status);

}

The output of this is:

string:
bytes: 948

As far as I can see 'result' should be holding the string which is 948 bytes in size but when trying to print it to the screen I am getting nothing, any ideas please?

Thanks, Geester

Originally Posted by vart

And what is the contents of the string? maybe there is just 0 as the first character?

It is a small string of xml, I have it working fine in PHP, looking at it with that script I just noticed that the beginning of the string contains some strange characters:

�

I assume this may be causing the problem? Any idea how to get around this please?

Thanks, Grant

Hmm, not sure if I did this correctly but I tried:

Code:

printf("%x\n",result);

And this is the output : a297b80

????


Thanks, Grant

read does not put a null terminator on the end of the string.

Originally Posted by geester

Hmm, not sure if I did this correctly but I tried:

Code:

printf("%x\n",result);

And this is the output : a297b80

????


Thanks, Grant

result is an array, and when used by itself it almost always decays down to a pointer to the first element, and %x means "print this integer in hexadecimal format". So, you printed the address of your buffer.

Maybe

Code:

printf("%c%c%c%c", result[0], result[1], result[2], result[3]);

to see the first characters of your result? And if you wanted more you could loop.

Thanks for all your help, Im only testing something at the moment and just need the first part of the string so looping this, as provided above:

Code:

printf("%c", result[x]);

does the job.

Thanks, Geester