IsBadReadPtr

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

BOOL IsBadReadPtr(
  CONST VOID *lp,  // address of memory block
  UINT ucb         // size of block
);
 

Parameters

lp

Pointer to the first byte of the memory block.

ucb

Specifies the size, in bytes, of the memory block. If this parameter is zero, the return value is zero.

Return Values

If the calling process has read access to all bytes in the specified memory range, the return value is zero.

If the calling process does not have read access to all bytes in the specified memory range, the return value is nonzero.

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.

In a preemptive multitasking environment, it is possible for some other thread to change the process's access to the memory being tested. Even when the function indicates that the process has read access to the specified memory, you should 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.

QuickInfo

  Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Requires version 1.0 or later.
  Header: Declared in winbase.h.
  Import Library: Use kernel32.lib.

See Also

Memory Management Overview, Memory Management Functions, IsBadCodePtr, IsBadStringPtr, IsBadWritePtr