AfxIsValidString

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

BOOL AfxIsValidString(
   LPCSTR lpsz,
   int nLength = -1 
); 

Parameters

• lpsz
  The pointer to test.

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

Return Value

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.

Example

// 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));   

Requirements

Header: afx.h

See Also

Concepts

MFC Macros and Globals

AfxIsMemoryBlock

AfxIsValidAddress