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vprintf functions

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Each of the vprintf functions takes a pointer to an argument list, then formats and writes the given data to a particular destination. The functions differ in several ways: in the parameter validation, whether the functions take single-byte or wide character strings, the output destination, and the support for specifying the order parameters are used in the format string.

_vcprintf, _vcwprintf
vfprintf, vfwprintf
_vfprintf_p, _vfprintf_p_l, _vfwprintf_p, _vfwprintf_p_l
vfprintf_s, _vfprintf_s_l, vfwprintf_s, _vfwprintf_s_l
vprintf, vwprintf
_vprintf_p, _vprintf_p_l, _vwprintf_p, _vwprintf_p_l
vprintf_s, _vprintf_s_l, vwprintf_s, _vwprintf_s_l
_vscprintf, _vscprintf_l, _vscwprintf, _vscwprintf_l
_vsnprintf, _vsnwprintf vsprintf, vswprintf
_vsprintf_p, _vsprintf_p_l, _vswprintf_p, _vswprintf_p_l
vsprintf_s, _vsprintf_s_l, vswprintf_s, _vswprintf_s_l

Remarks

The vprintf functions are similar to their counterpart functions as listed in the following table. However, each vprintf function accepts a pointer to an argument list, whereas each of the counterpart functions accepts an argument list.

These functions format data for output to destinations as follows.

Function Counterpart function Output destination Parameter Validation Positional Parameter Support
_vcprintf _cprintf console Check for null. no
_vcwprintf _cwprintf console Check for null. no
vfprintf fprintf stream Check for null. no
vfprintf_p fprintf_p stream Check for null and valid format. yes
vfprintf_s fprintf_s stream Check for null and valid format. no
vfwprintf fwprintf stream Check for null. no
vfwprintf_p fwprintf_p stream Check for null and valid format. yes
vfwprintf_s fwprintf_s stream Check for null and valid format. no
vprintf printf stdout Check for null. no
vprintf_p printf_p stdout Check for null and valid format. yes
vprintf_s printf_s stdout Check for null and valid format. no
vwprintf wprintf stdout Check for null. no
vwprintf_p wprintf_p stdout Check for null and valid format. yes
vwprintf_s wprintf_s stdout Check for null and valid format. no
vsprintf sprintf memory pointed to by buffer Check for null. no
vsprintf_p sprintf_p memory pointed to by buffer Check for null and valid format. yes
vsprintf_s sprintf_s memory pointed to by buffer Check for null and valid format. no
vswprintf swprintf memory pointed to by buffer Check for null. no
vswprintf_p swprintf_p memory pointed to by buffer Check for null and valid format. yes
vswprintf_s swprintf_s memory pointed to by buffer Check for null and valid format. no
_vscprintf _vscprintf memory pointed to by buffer Check for null. no
_vscwprintf _vscwprintf memory pointed to by buffer Check for null. no
_vsnprintf _snprintf memory pointed to by buffer Check for null. no
_vsnwprintf _snwprintf memory pointed to by buffer Check for null. no

The argptr argument has type va_list, which is defined in VARARGS.H and STDARG.H. The argptr variable must be initialized by va_start, and may be reinitialized by subsequent va_arg calls; argptr then points to the beginning of a list of arguments that are converted and transmitted for output according to the corresponding specifications in the format argument. format has the same form and function as the format argument for printf. None of these functions invoke va_end. For a more complete description of each vprintf function, see the description of its counterpart function as listed in the preceding table.

_vsnprintf differs from vsprintf in that it writes no more than count bytes to buffer.

The versions of these functions with the w infix in the name are wide-character versions of the corresponding functions without the w infix; in each of these wide-character functions, buffer and format are wide-character strings. Otherwise, each wide-character function behaves identically to its SBCS counterpart function.

The versions of these functions with _s and _p suffixes are the more secure versions. These versions validate the format strings. They'll generate an exception if the format string isn't well formed (for example, if invalid formatting characters are used).

The versions of these functions with the _p suffix let you specify the order in which the supplied arguments are substituted in the format string. For more information, see printf_p Positional Parameters.

For vsprintf, vswprintf, _vsnprintf and _vsnwprintf, if copying occurs between strings that overlap, the behavior is undefined.

Important

Ensure that format is not a user-defined string. For more information, see Avoiding buffer overruns. If using the secure versions of these functions (either the _s or _p suffixes), a user-supplied format string could trigger an invalid parameter exception if the user-supplied string contains invalid formatting characters.

See also

Stream I/O
fprintf, _fprintf_l, fwprintf, _fwprintf_l
printf, _printf_l, wprintf, _wprintf_l
sprintf, _sprintf_l, swprintf, _swprintf_l, __swprintf_l
va_arg, va_copy, va_end, va_start