_strdate_s, _wstrdate_s

아티클
01/05/2008

Copy the current system date to a buffer. These are versions of _strdate, _wstrdate with security enhancements as described in Security Enhancements in the CRT.

errno_t _strdate_s(
   char *buffer,
   size_t numberOfElements
);
errno_t _wstrdate_s(
   wchar_t *buffer,
   size_t numberOfElements
);
template <size_t size>
errno_t _strdate_s(
   char (&buffer)[size]
); // C++ only
template <size_t size>
errno_t _wstrdate_s(
   wchar_t (&buffer)[size]
); // C++ only

Parameters

[out] buffer
A pointer to a buffer which will be filled in with the formatted date string.
[in] numberOfElements
Size of the buffer.

Return Value

Zero if successful. The return value is an error code if there is a failure. Error codes are defined in ERRNO.H; see table below for the exact errors generated by this function. For more information on error codes, see errno.

Error Conditions

buffer	numberOfElements	Return	Contents of buffer
NULL	(any)	EINVAL	Not modified
Not NULL (pointing to valid buffer)	0	EINVAL	Not modified
Not NULL (pointing to valid buffer)	0 < numberOfElements < 9	EINVAL	Empty string
Not NULL (pointing to valid buffer)	numberOfElements >= 9	0	Current date formatted as specified in the remarks

Security Issues

Passing in an invalid non NULL value for the buffer will result in an access violation if the numberOfElements parameter is greater than 9.

Passing values for size that is greater than the actual size of the buffer will result in buffer overrun.

Remarks

These functions provide more secure versions of _strdate and _wstrdate. The _strdate_s function copies the current system date to the buffer pointed to by buffer, formatted mm/dd/yy, where mm is two digits representing the month, dd is two digits representing the day, and yy is the last two digits of the year. For example, the string 12/05/99 represents December 5, 1999. The buffer must be at least 9 bytes long.

_wstrdate_s is a wide-character version of _strdate_s; the argument and return value of _wstrdate_s are wide-character strings. These functions behave identically otherwise.

If buffer is a NULL pointer, or if numberOfElements is less than 9 characters, the invalid parameter handler is invoked, as described in Parameter Validation. If execution is allowed to continue, these functions return -1 and set errno to EINVAL if the buffer is NULL or if numberOfElements is less than or equal to 0, or set errno to ERANGE if numberOfElements is less than 9.

In C++, using these functions is simplified by template overloads; the overloads can infer buffer length automatically (eliminating the need to specify a size argument) and they can automatically replace older, non-secure functions with their newer, secure counterparts. For more information, see Secure Template Overloads.

Generic-Text Routine Mapping:

TCHAR.H routine	_UNICODE & _MBCS not defined	_MBCS defined	_UNICODE defined
_tstrdate_s	_strdate_s	_strdate_s	_wstrdate_s

Requirements

Routine	Required header
_strdate	<time.h>
_wstrdate	<time.h> or <wchar.h>

Example

See the example for time.

.NET Framework Equivalent

System::DateTime::Parse

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