| **Navigation:**  [[advanced topics 1.htm|Advanced Topics]] > Legacy Project System Reference >====== Check #pragmas ====== | [[call pragmas.htm|{{btn_prev_n.gif|Previous page}}]][[advanced topics 1.htm|{{btn_home_n.gif|Return to chapter overview}}]][[code pragmas 1.htm|{{btn_next_n.gif|Next page}}]] |
|  ||

#pragmas with the class name //check// control run-time error checking. These can help you to locate erroneous program logic, but at the expense of slower execution. All these #pragmas default to off.

When a run-time check detects an error, the default action is to terminate the process and create the file CWLOG.TXT.

The following check #pragmas are available:

**#pragma check(guard => on | off)**

**#pragma check(index => on | off)**

**#pragma check(nil_ptr => on | off)**

**#pragma check(overflow => on | off)**

**#pragma check(range => on | off)**

**#pragma check(stack => on | off)**

{{notebox.jpg|NoteBox.jpg}}

**A pragma can be used in the Project language, C++ code, Modula-2 code, or Clarion code. Some only work in certain places. A ****'P'**** to the right of the pragma indicates it can be used in the Project language, a ****'C'**** indicates it can be used in C++ code, a ****'M'**** indicates it can be used in Modula-2 code, and a ****'W' ****indicates that it can be used in Clarion code (CLW files).**

**#pragma check(stack => on | off)    cpmw**

When on, the run-time system checks that your program does not run out of stack space. You can increase the size of the stack using the data(stack_size) #pragma.

**#pragma check(nil_ptr => on | off)    cpmw**

When on, the run-time system checks for any dereference of NULL or NIL pointers.

**#pragma check(range => on | off)    pm**

When on, a range check is performed whenever a value is assigned to a variable of subrange or enumerated type. In addition, compile-time values are checked to ensure that they are in the range of their type.

**#pragma check(overflow => on | off)    pm**

When on, the run-time system checks that numeric values do not go out of range.

**#pragma check(index => on | off)    cpmw**

When on, the run-time system checks for the use of an array index larger than the array size.

**#pragma check(guard => on | off)    pm**

This #pragma controls whether checks are performed on the checked-guard operator.