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StringCchLengthA function (strsafe.h)

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Determines whether a string exceeds the specified length, in characters.

StringCchLength is a replacement for the following functions:

Syntax

STRSAFEAPI StringCchLengthA(
  [in]  STRSAFE_PCNZCH psz,
  [in]  size_t         cchMax,
  [out] size_t         *pcchLength
);

Parameters

[in] psz

Type: LPCTSTR

The string whose length is to be checked.

[in] cchMax

Type: size_t

The maximum number of characters allowed in psz, including the terminating null character. This value cannot exceed STRSAFE_MAX_CCH.

[out] pcchLength

Type: size_t*

The number of characters in psz, not including the terminating null character. This value is valid only if pcch is not NULL and the function succeeds.

Return value

Type: HRESULT

This function can return one of the following values. It is strongly recommended that you use the SUCCEEDED and FAILED macros to test the return value of this function.

Return code Description
S_OK
 The string at psz was not NULL, and the length of the string (including the terminating null character) is less than or equal to cchMax characters.
STRSAFE_E_INVALID_PARAMETER
 The value in psz is NULL, cchMax is larger than STRSAFE_MAX_CCH, or psz is longer than cchMax.
 

Note that this function returns an HRESULT value, unlike the functions that it replaces.

Remarks

Compared to the functions it replaces, StringCchLength is an additional tool for proper buffer handling in your code. Poor buffer handling is implicated in many security issues that involve buffer overruns.

StringCchLength can be used in its generic form, or in its more specific forms. The data type of the string determines the form of this function that you should use.

String Data Type String Literal Function
char "string" StringCchLengthA
TCHAR TEXT("string") StringCchLength
WCHAR L"string" StringCchLengthW
 

UnalignedStringCchLength is an alias for this function.

Note

The strsafe.h header defines StringCchLength as an alias which automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes.

Requirements

Requirement Value
Minimum supported client Windows XP with SP2 [desktop apps | UWP apps]
Minimum supported server Windows Server 2003 with SP1 [desktop apps | UWP apps]
Target Platform Windows
Header strsafe.h

See also

StringCbLength