Ok added the "\n":
Qt Code: 
  1. proc->addArgument( username );
  2. 	proc->addArgument( database );
  3. 	output->append( (proc->arguments()).join(" "));
  4.     proc->start();
  5.  
  6. 	proc->writeToStdin("Saurabh\n");
  7.     connect( proc, SIGNAL(readyReadStdout()),
  8.             this, SLOT(readFromStdout()) );
  9.  
  10.     if ( !proc->start() )
  11.     {
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But still nothing. Here is the .c code:
Qt Code: 
  1. int SetQuery()
  2. {		char query[1024];
  3. 		char serialnmr[20];
  4. 		//char *serialnmr;
  5. 		//serialnmr = "Saurabh";
  6. 		printf("input");
  7. 		scanf("%s",serialnmr);
  8.  
  9. 		printf("%s\n",serialnmr);
  10. 		sprintf(query, "SELECT * FROM users WHERE name='%s'",serialnmr);
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The .c works in the command line but using QT3 it doesn't want to work.