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Use this function to determine whether a pointer to a string is valid.

BOOL AfxIsValidString( 
   LPCSTR lpsz, 
   int nLength = -1  


The pointer to test.


Specifies the length of the string to be tested, in bytes. A value of –1 indicates that the string will be null-terminated.

In debug builds, nonzero if the specified pointer points to a string of the specified size; otherwise 0.

In non-debug builds, nonzero if lpsz is not NULL; otherwise 0.

// Create a character string which should be valid. 
char str[12] = "hello world";

// Create a null pointer, which should be an invalid string. 
char* null = (char*)0x0;

ASSERT(AfxIsValidString(str, 12));
ASSERT(!AfxIsValidString(null, 5));   

Header: afx.h

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