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4/8/2010

This function verifies that the calling process has read access to the specified range of memory.

Syntax 

BOOL IsBadReadPtr(
  const void* 
lp,
  UINT 
ucb
);

Parameters

lp

[in] Pointer to the first byte of the memory block.

ucb

[in] Specifies the size, in bytes, of the memory block.

If this parameter is zero, the return value is zero.

Return Value

Zero indicates that the calling process has read access to all bytes in the specified memory range. Nonzero indicates that the calling process does not have read access to all bytes in the specified memory range.

If the application is compiled as a debugging version and the process does not have read access to all bytes in the specified memory range, the function causes an assertion and breaks into the debugger. Leaving the debugger, the function continues as usual and returns a nonzero value. This behavior is by design, as a debugging aid.

Remarks

If the calling process has read access to some, but not all, of the bytes in the specified memory range, the return value is nonzero.

When running in kernel mode, any pointer over 0x80000000 is returned as valid.

In a pre-emptive multitasking environment, another thread could change the access of the process to the memory being tested.

Even when the function indicates that the process has read access to the specified memory, use structured exception handling when attempting to access the memory.

Use of structured exception handling enables the system to notify the process if an access violation exception occurs, giving the process an opportunity to handle the exception.

Requirements

Header winbase.h
Library coredll.lib
Windows Embedded CE Windows CE 1.0 and later
Windows Mobile Windows Mobile Version 5.0 and later

See Also