viPrintf(vi, "OUTPut2 on\n");      
 // Turn sweep on 
 viPrintf(vi, "SWEep2:STATe ON\n");   
 
 ViChar  err_msg[256]; 
 ViInt32 err_num; 
 
 // Check for first error 
 viQueryf(vi, "SYSTem:ERRor?\n", "%d,%t", &err_num, err_msg); 
 printf("Error Number: %d; Error Message: %s\n", err_num, 
     err_msg); 
 /* Close session */ 
 viClose (vi); 
 viClose (viRm); 
 
 return 0; 
}