National Instruments 320685D-01 Dynamic Memory Protection Errors , Memory Deallocation (Non-Fatal) , Memory Corruption (Fatal) , General Protection Errors , Library Protection Errors

Chapter 1 LabWindows/CVI Compiler
© National Instruments Corporation 1-11 LabWindows/CVI Programmer Reference Manual
Dynamic Memory Protection Errors
Dynamic memory protection errors report illegal operations with dynamic memory and
corrupted dynamic memory during allocation and deallocation.
Memory Deallocation (Non-Fatal)
LabWindows/CVI generates memory deallocation errors when the pointer is not the result of
a memory allocation. The following user protection errors involve memory deallocation:
• Attempt to free uninitialized pointer
• Attempt to free pointer to freed memory
• Attempt to free invalid pointer expression
• Attempt to free pointer not allocated with malloc or calloc
Memory Corruption (Fatal)
LabWindows/CVI generates memory corruption errors when a memory
allocation/deallocation detects corrupted memory. During each dynamic memory operation,
LabWindows/CVI verifies the integrity of the memory blocks it uses in the operation. When
you set the Debugging Level to Extended, LabWindo ws/CVI thoroug hly chec ks all dynamic
memory on each memory operation. LabWindows/CVI generates the following error when it
discovers a problem: Dynamic memory is corrupt.
General Protection Errors
LabWindows/CVI also checks for stack overflow and missing return values:
• Stack overflow (fatal)
• Missing return value (non-fatal)
The missing return value error means that a non-void function (one you do not declare with
void return type) returned, but did not returned a value.
Library Protection Errors
Library functions sometimes generate errors when they receive invalid arguments.
LabWindows/CVI error checking is sensitive to the requirements of each library function.
The following errors involve library protection:
• Null pointer argument to library function
• Uninitialized pointer argument to library function
• Passing a pointer to freed memory to a library function
• Array argument too small
• Passing by reference a scalar argument to a library function that expects an array
00ProRef.book : 06chap01.fm Page 11 Monday, March 9, 1998 3:23 PM