PurifyPreDidAlloc

Custom Memory Allocation Example

Related Topics

Description

Provides Purify with information about a pending memory block lookup. Call this function right before invoking custom code that checks for the existence of a memory block.

Syntax

void *PurifyPreDidAlloc(void *pRequest, unsigned int dwFlags)

 

pRequest

The address of the block whose existence is to be determined, within its red zones. 

dwFlags

May include any of the following flags, or 0 to indicate none of them: 

 

Flag 

Meaning

PURIFY_TRACK_AS_HEAP 

The block is allocated within a Windows heap

PURIFY_TRACK_NO_REDZONE 

Purify should not pad the block with red zones

Returns

Where n is the actual base (including red zones) of the block whose existence is to be determined

Notes

§      This function supplies Purify with information about a pending memory block lookup. If Purify is tracking the memory block, this function provides its actual base address, for use by your custom code that determines the block's existence. This actual base address value includes the red zones that provide Purify array-bounds detection to any of your code that uses the block. Use this function in conjunction with the PurifyPostDidAlloc() function, which indicates to Purify that the block lookup is complete.

§      This function is a member of Purify's memory tracking interface. The example code provided for Purify's memory tracking interface demonstrates this function.

§      This function is necessary only for memory blocks that have been created by custom allocation routines. Purify automatically intercepts standard Windows and C runtime API functions.

(C) Copyright IBM Corporation 1992, 2010.