Bug in fprintf/fscanf

Bug in fprintf/fscanf

[Martin Laabs]

Hello,

could someone please verify the following bug I discovered. It seems that 
fprintf (or fputs) fails after a fscanf call. The second fprintf call 
however does work as expected.
I currently use the network as stream. Maybe this bug is because I use the 
fdopen function but at the moment I do not have an other working file 
descriptor.


Follwoing Code:

    term=fdopen(clntSock, "r+");
    assert(term!=0);

    while(1)
	{
	  fprintf(term, "Type a number\n");
	  diag_printf("fscanf %d\n", fscanf(term, "%d",&num));
	  diag_printf("fprintf1 %d\n",fprintf(term, "Number was %d\n",num));
   	  diag_printf("fprintf2 %d\n",fprintf(term, "Again - Number was 
%d\n",num));
	}

Produces following output (with Input of 8, 9 and 10):

Type a number
8
Again - Number was 8
Type a number
9
Again - Number was 9
Type a number
10
Again - Number was 10
Type a number


With diag output of:

fscanf 1
fprintf1 0
fprintf2 21
fscanf 1
fprintf1 0
fprintf2 21
fscanf 1
fprintf1 0
fprintf2 22

The complete code is available under http://pastebin.com/8iYVkAhz

Greetings,

  Martin Laabs