StringCbGetsA function (strsafe.h)

Article
02/09/2023

Gets one line of text from stdin, up to and including the newline character ('\n'). The line of text is copied to the destination buffer, and the newline character is replaced with a null character. The size of the destination buffer is provided to the function to ensure that it does not write past the end of this buffer.

Note This function can only be used inline.

StringCbGets is a replacement for the following functions:

gets, _getws, _getts

StringCbGets is not a replacement for fgets, which does not replace newline characters with a terminating null character.

Syntax

STRSAFEAPI StringCbGetsA(
  [out] STRSAFE_LPSTR pszDest,
  [in]  size_t        cbDest
);

Parameters

[out] pszDest

Type: LPTSTR

The destination buffer, which receives the input.

[in] cbDest

Type: size_t

The size of the destination buffer, in bytes. This value must be greater than sizeof(TCHAR) for the function to succeed. The maximum number of bytes allowed is STRSAFE_MAX_CCH * sizeof(TCHAR). If cbDest is too small to hold the full line of text, the data is truncated.

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	Data was read from stdin, was copied to the buffer at pszDest, and the buffer was null-terminated.
STRSAFE_E_END_OF_FILE	Indicates an error or end-of-file condition. Use feof or ferror to determine which one has occurred.
STRSAFE_E_INVALID_PARAMETER	The value in cbDest is larger than the maximum allowed value.
STRSAFE_E_INSUFFICIENT_BUFFER	The value in cbDest is `sizeof(TCHAR)` or less.

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

Remarks

StringCbGets provides additional processing for proper buffer handling in your code. Poor buffer handling is implicated in many security issues that involve buffer overruns. StringCbGets always null-terminates a nonzero-length destination buffer.

The value of pszDest should not be NULL. See StringCbGetsEx if you require the handling of null string pointer values.

StringCbGets 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, as shown in the following table.

String Data Type	String Literal	Function
char	"string"	StringCbGetsA
TCHAR	TEXT("string")	StringCbGets
WCHAR	L"string"	StringCbGetsW

Note

The strsafe.h header defines StringCbGets 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