gets_s, _getws_s

Article
06/05/2017

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The latest version of this topic can be found at gets_s, _getws_s.

Gets a line from the stdin stream. These versions of gets, _getws have security enhancements, as described in Security Features in the CRT.

Syntax

char *gets_s(   
   char *buffer,  
   size_t sizeInCharacters  
);  
wchar_t *_getws_s(   
   wchar_t *buffer,  
   size_t sizeInCharacters  
);  
template <size_t size>  
char *gets_s(   
   char (&buffer)[size]  
); // C++ only  
template <size_t size>  
wchar_t *_getws_s(   
   wchar_t (&buffer)[size]  
); // C++ only

Parameters

[out] buffer
Storage location for input string.

[in] sizeInCharacters
The size of the buffer.

Return Value

Returns buffer if successful. A NULL pointer indicates an error or end-of-file condition. Use ferror or feof to determine which one has occurred.

Remarks

The gets_s function reads a line from the standard input stream stdin and stores it in buffer. The line consists of all characters up to and including the first newline character ('\n'). gets_s then replaces the newline character with a null character ('\0') before returning the line. In contrast, the fgets_s function retains the newline character.

If the first character read is the end-of-file character, a null character is stored at the beginning of buffer and NULL is returned.

_getws is a wide-character version of gets_s; its argument and return value are wide-character strings.

If buffer is NULL or sizeInCharacters is less than or equal to zero, or if the buffer is too small to contain the input line and null terminator, these functions invoke an invalid parameter handler, as described in Parameter Validation. If execution is allowed to continue, these functions return NULL and set errno to ERANGE.

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 Mappings

TCHAR.H routine	_UNICODE & _MBCS not defined	_MBCS defined	_UNICODE defined
`_getts`	`gets_s`	`gets_s`	`_getws`

Requirements

Routine	Required header
`gets_s`	<stdio.h>
`_getws`	<stdio.h> or <wchar.h>

The console is not supported in Windows 8.x Store apps. The standard stream handles that are associated with the console—stdin, stdout, and stderr—must be redirected before C run-time functions can use them in Windows 8.x Store apps. For additional compatibility information, see Compatibility.

Example

// crt_gets_s.c  
// This program retrieves a string from the stdin and   
// prints the same string to the console.  
  
#include <stdio.h>  
  
int main( void )  
{  
   char line[21]; // room for 20 chars + '\0'  
   gets_s( line, 20 );  
   printf( "The line entered was: %s\n", line );  
}

  
Hello there!The line entered was: Hello there!

.NET Framework Equivalent

System::Console::Read

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