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Original file line number Diff line number Diff line change
Expand Up @@ -19,173 +19,173 @@ author: "corob-msft"
ms.author: "corob"
manager: "ghogen"
ms.workload: ["cplusplus"]
---
# vsprintf, _vsprintf_l, vswprintf, _vswprintf_l, __vswprintf_l
Write formatted output using a pointer to a list of arguments. More secure versions of these functions are available; see [vsprintf_s, _vsprintf_s_l, vswprintf_s, _vswprintf_s_l](../../c-runtime-library/reference/vsprintf-s-vsprintf-s-l-vswprintf-s-vswprintf-s-l.md).

## Syntax

```
int vsprintf(
char *buffer,
const char *format,
va_list argptr
);
int _vsprintf_l(
char *buffer,
const char *format,
locale_t locale,
va_list argptr
);
int vswprintf(
wchar_t *buffer,
size_t count,
const wchar_t *format,
va_list argptr
);
int _vswprintf_l(
wchar_t *buffer,
size_t count,
const wchar_t *format,
locale_t locale,
va_list argptr
);
int __vswprintf_l(
wchar_t *buffer,
const wchar_t *format,
locale_t locale,
va_list argptr
);
template <size_t size>
int vsprintf(
char (&buffer)[size],
const char *format,
va_list argptr
); // C++ only
template <size_t size>
int _vsprintf_l(
char (&buffer)[size],
const char *format,
locale_t locale,
va_list argptr
); // C++ only
template <size_t size>
int vswprintf(
wchar_t (&buffer)[size],
const wchar_t *format,
va_list argptr
); // C++ only
template <size_t size>
int _vswprintf_l(
wchar_t (&buffer)[size],
const wchar_t *format,
locale_t locale,
va_list argptr
); // C++ only
```

#### Parameters
`buffer`
Storage location for output.

`count`
Maximum number of characters to store, in the `UNICODE` version of this function.

`format`
Format specification.

`argptr`
Pointer to list of arguments.

`locale`
The locale to use.

## Return Value
`vsprintf` and `vswprintf` return the number of characters written, not including the terminating null character, or a negative value if an output error occurs. If `buffer` or `format` is a null pointer, these functions invoke the invalid parameter handler, as described in [Parameter Validation](../../c-runtime-library/parameter-validation.md). If execution is allowed to continue, these functions return -1 and set `errno` to `EINVAL`.

For information on these and other error codes, see [_doserrno, errno, _sys_errlist, and _sys_nerr](../../c-runtime-library/errno-doserrno-sys-errlist-and-sys-nerr.md).

## Remarks
Each of these functions takes a pointer to an argument list, and then formats and writes the given data to the memory pointed to by `buffer`.

The versions of these functions with the `_l` suffix are identical except that they use the locale parameter passed in instead of the current thread locale.

> [!IMPORTANT]
> Using `vsprintf`, here is no way to limit the number of characters written, which means that code using this function is susceptible to buffer overruns. Use [_vsnprintf](../../c-runtime-library/reference/vsnprintf-vsnprintf-vsnprintf-l-vsnwprintf-vsnwprintf-l.md) instead, or call [_vscprintf](../../c-runtime-library/reference/vscprintf-vscprintf-l-vscwprintf-vscwprintf-l.md) to determine how large a buffer is needed. Also, ensure that `format` is not a user-defined string. For more information, see [Avoiding Buffer Overruns](http://msdn.microsoft.com/library/windows/desktop/ms717795).

`vswprintf` conforms to the ISO C Standard, which requires the second parameter, `count`, of type `size_t`. To force the old nonstandard behavior, define `_CRT_NON_CONFORMING_SWPRINTFS.` The old behavior may not be in a future version, so code should be changed to use the new conformant behavior.

In C++, these functions have template overloads that invoke the newer, secure counterparts of these functions. For more information, see [Secure Template Overloads](../../c-runtime-library/secure-template-overloads.md).

### Generic-Text Routine Mappings

|TCHAR.H routine|_UNICODE & _MBCS not defined|_MBCS defined|_UNICODE defined|
|---------------------|------------------------------------|--------------------|-----------------------|
|`_vstprintf`|`vsprintf`|`vsprintf`|`vswprintf`|
|`_vstprintf_l`|`_vsprintf_l`|`_vsprintf_l`|`_vswprintf_l`|

## Requirements

|Routine|Required header|Optional headers|
|-------------|---------------------|----------------------|
|`vsprintf`, `_vsprintf_l`|\<stdio.h> and \<stdarg.h>|\<varargs.h>*|
|`vswprintf`, `_vswprintf_l`|\<stdio.h> or \<wchar.h>, and \<stdarg.h>|\<varargs.h>*|

\* Required for UNIX V compatibility.

For additional compatibility information, see [Compatibility](../../c-runtime-library/compatibility.md) in the Introduction.

## Example

```
// crt_vsprintf.c
// compile with: /W3
// This program uses vsprintf to write to a buffer.
// The size of the buffer is determined by _vscprintf.

#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>

void test( char * format, ... )
{
va_list args;
int len;
char *buffer;

// retrieve the variable arguments
va_start( args, format );

len = _vscprintf( format, args ) // _vscprintf doesn't count
+ 1; // terminating '\0'

buffer = (char*)malloc( len * sizeof(char) );

vsprintf( buffer, format, args ); // C4996
// Note: vsprintf is deprecated; consider using vsprintf_s instead
puts( buffer );

free( buffer );
va_end( args );
}

int main( void )
{
test( "%d %c %d", 123, '<', 456 );
test( "%s", "This is a string" );
}
```

```Output
123 < 456
This is a string
```

## See Also
[Stream I/O](../../c-runtime-library/stream-i-o.md)
[vprintf Functions](../../c-runtime-library/vprintf-functions.md)
[Format Specification Syntax: printf and wprintf Functions](../../c-runtime-library/format-specification-syntax-printf-and-wprintf-functions.md)
[fprintf, _fprintf_l, fwprintf, _fwprintf_l](../../c-runtime-library/reference/fprintf-fprintf-l-fwprintf-fwprintf-l.md)
[printf, _printf_l, wprintf, _wprintf_l](../../c-runtime-library/reference/printf-printf-l-wprintf-wprintf-l.md)
[sprintf, _sprintf_l, swprintf, _swprintf_l, \__swprintf_l](../../c-runtime-library/reference/sprintf-sprintf-l-swprintf-swprintf-l-swprintf-l.md)
[va_arg, va_copy, va_end, va_start](../../c-runtime-library/reference/va-arg-va-copy-va-end-va-start.md)
---
# vsprintf, _vsprintf_l, vswprintf, _vswprintf_l, __vswprintf_l
Write formatted output using a pointer to a list of arguments. More secure versions of these functions are available; see [vsprintf_s, _vsprintf_s_l, vswprintf_s, _vswprintf_s_l](../../c-runtime-library/reference/vsprintf-s-vsprintf-s-l-vswprintf-s-vswprintf-s-l.md).
## Syntax
```
int vsprintf(
char *buffer,
const char *format,
va_list argptr
);
int _vsprintf_l(
char *buffer,
const char *format,
locale_t locale,
va_list argptr
);
int vswprintf(
wchar_t *buffer,
size_t count,
const wchar_t *format,
va_list argptr
);
int _vswprintf_l(
wchar_t *buffer,
size_t count,
const wchar_t *format,
locale_t locale,
va_list argptr
);
int __vswprintf_l(
wchar_t *buffer,
const wchar_t *format,
locale_t locale,
va_list argptr
);
template <size_t size>
int vsprintf(
char (&buffer)[size],
const char *format,
va_list argptr
); // C++ only
template <size_t size>
int _vsprintf_l(
char (&buffer)[size],
const char *format,
locale_t locale,
va_list argptr
); // C++ only
template <size_t size>
int vswprintf(
wchar_t (&buffer)[size],
const wchar_t *format,
va_list argptr
); // C++ only
template <size_t size>
int _vswprintf_l(
wchar_t (&buffer)[size],
const wchar_t *format,
locale_t locale,
va_list argptr
); // C++ only
```
#### Parameters
`buffer`
Storage location for output.
`count`
Maximum number of characters to store, in the `UNICODE` version of this function.
`format`
Format specification.
`argptr`
Pointer to list of arguments.
`locale`
The locale to use.
## Return Value
`vsprintf` and `vswprintf` return the number of characters written, not including the terminating null character, or a negative value if an output error occurs. If `buffer` or `format` is a null pointer, these functions invoke the invalid parameter handler, as described in [Parameter Validation](../../c-runtime-library/parameter-validation.md). If execution is allowed to continue, these functions return -1 and set `errno` to `EINVAL`.
For information on these and other error codes, see [_doserrno, errno, _sys_errlist, and _sys_nerr](../../c-runtime-library/errno-doserrno-sys-errlist-and-sys-nerr.md).
## Remarks
Each of these functions takes a pointer to an argument list, and then formats and writes the given data to the memory pointed to by `buffer`.
The versions of these functions with the `_l` suffix are identical except that they use the locale parameter passed in instead of the current thread locale.
> [!IMPORTANT]
> Using `vsprintf`, there is no way to limit the number of characters written, which means that code using this function is susceptible to buffer overruns. Use [_vsnprintf](../../c-runtime-library/reference/vsnprintf-vsnprintf-vsnprintf-l-vsnwprintf-vsnwprintf-l.md) instead, or call [_vscprintf](../../c-runtime-library/reference/vscprintf-vscprintf-l-vscwprintf-vscwprintf-l.md) to determine how large a buffer is needed. Also, ensure that `format` is not a user-defined string. For more information, see [Avoiding Buffer Overruns](http://msdn.microsoft.com/library/windows/desktop/ms717795).
`vswprintf` conforms to the ISO C Standard, which requires the second parameter, `count`, of type `size_t`. To force the old nonstandard behavior, define `_CRT_NON_CONFORMING_SWPRINTFS.` The old behavior may not be in a future version, so code should be changed to use the new conformant behavior.
In C++, these functions have template overloads that invoke the newer, secure counterparts of these functions. For more information, see [Secure Template Overloads](../../c-runtime-library/secure-template-overloads.md).
### Generic-Text Routine Mappings
|TCHAR.H routine|_UNICODE & _MBCS not defined|_MBCS defined|_UNICODE defined|
|---------------------|------------------------------------|--------------------|-----------------------|
|`_vstprintf`|`vsprintf`|`vsprintf`|`vswprintf`|
|`_vstprintf_l`|`_vsprintf_l`|`_vsprintf_l`|`_vswprintf_l`|
## Requirements
|Routine|Required header|Optional headers|
|-------------|---------------------|----------------------|
|`vsprintf`, `_vsprintf_l`|\<stdio.h> and \<stdarg.h>|\<varargs.h>*|
|`vswprintf`, `_vswprintf_l`|\<stdio.h> or \<wchar.h>, and \<stdarg.h>|\<varargs.h>*|
\* Required for UNIX V compatibility.
For additional compatibility information, see [Compatibility](../../c-runtime-library/compatibility.md) in the Introduction.
## Example
```
// crt_vsprintf.c
// compile with: /W3
// This program uses vsprintf to write to a buffer.
// The size of the buffer is determined by _vscprintf.
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
void test( char * format, ... )
{
va_list args;
int len;
char *buffer;
// retrieve the variable arguments
va_start( args, format );
len = _vscprintf( format, args ) // _vscprintf doesn't count
+ 1; // terminating '\0'
buffer = (char*)malloc( len * sizeof(char) );
vsprintf( buffer, format, args ); // C4996
// Note: vsprintf is deprecated; consider using vsprintf_s instead
puts( buffer );
free( buffer );
va_end( args );
}
int main( void )
{
test( "%d %c %d", 123, '<', 456 );
test( "%s", "This is a string" );
}
```
```Output
123 < 456
This is a string
```
## See Also
[Stream I/O](../../c-runtime-library/stream-i-o.md)
[vprintf Functions](../../c-runtime-library/vprintf-functions.md)
[Format Specification Syntax: printf and wprintf Functions](../../c-runtime-library/format-specification-syntax-printf-and-wprintf-functions.md)
[fprintf, _fprintf_l, fwprintf, _fwprintf_l](../../c-runtime-library/reference/fprintf-fprintf-l-fwprintf-fwprintf-l.md)
[printf, _printf_l, wprintf, _wprintf_l](../../c-runtime-library/reference/printf-printf-l-wprintf-wprintf-l.md)
[sprintf, _sprintf_l, swprintf, _swprintf_l, \__swprintf_l](../../c-runtime-library/reference/sprintf-sprintf-l-swprintf-swprintf-l-swprintf-l.md)
[va_arg, va_copy, va_end, va_start](../../c-runtime-library/reference/va-arg-va-copy-va-end-va-start.md)