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This function determines whether the calling process has read access to the memory at the specified address.


BOOL IsBadCodePtr(



[in] Pointer to an address in memory.

Return Value

Zero indicates that the calling process has read access to the specified memory. Nonzero indicates that the calling process does not have read access to the specified memory. To get extended error information, call GetLastError.

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.


IsBadCodePtrchecks the read access only at the specified address and does not guarantee read access to a range of memory.

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.


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