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_strrev, _wcsrev, _mbsrev, _mbsrev_l

  • Άρθρο

Reverses the characters of a string.

Important

_mbsrev and _mbsrev_l cannot be used in applications that execute in the Windows Runtime. For more information, see CRT functions not supported in Universal Windows Platform apps.

Syntax

char *_strrev(
   char *str
);
wchar_t *_wcsrev(
   wchar_t *str
);
unsigned char *_mbsrev(
   unsigned char *str
);
unsigned char *_mbsrev_l(
   unsigned char *str,
   _locale_t locale
);

Parameters

str
Null-terminated string to reverse.

locale
Locale to use.

Return value

Returns a pointer to the altered string. No return value is reserved to indicate an error.

Remarks

The _strrev function reverses the order of the characters in str. The terminating null character remains in place. _wcsrev and _mbsrev are wide-character and multibyte-character versions of _strrev. The arguments and return value of _wcsrev are wide-character strings. The arguments and return value of _mbsrev are multibyte-character strings. For _mbsrev, the order of bytes in each multibyte character in str isn't changed. These three functions behave identically otherwise.

_mbsrev validates its parameters. If either string1 or string2 is a null pointer, the invalid parameter handler is invoked, as described in Parameter validation. If execution is allowed to continue, _mbsrev returns NULL and sets errno to EINVAL. _strrev and _wcsrev don't validate their parameters.

The output value is affected by the setting of the LC_CTYPE category setting of the locale. For more information, see setlocale. The versions of these functions are identical, except that the ones that don't have the _l suffix use the current locale and the ones that do have the _l suffix instead use the locale parameter that's passed in. For more information, see Locale.

Important

These functions might be vulnerable to buffer overrun threats. Buffer overruns can be used for system attacks because they can cause an unwarranted elevation of privilege. For more information, see Avoiding buffer overruns.

By default, this function's global state is scoped to the application. To change this behavior, see Global state in the CRT.

Generic-text routine mappings

TCHAR.H routine _UNICODE and _MBCS not defined _MBCS defined _UNICODE defined
_tcsrev _strrev _mbsrev _wcsrev
n/a n/a _mbsrev_l n/a

Requirements

Routine Required header
_strrev <string.h>
_wcsrev <string.h> or <wchar.h>
_mbsrev, _mbsrev_l <mbstring.h>

For more compatibility information, see Compatibility.

Example

// crt_strrev.c
// This program checks a string to see
// whether it is a palindrome: that is, whether
// it reads the same forward and backward.
//

#include <string.h>
#include <stdio.h>

int main( void )
{
   char* string = "Able was I ere I saw Elba";
   int result;

   // Reverse string and compare (ignore case):
   result = _stricmp( string, _strrev( _strdup( string ) ) );
   if( result == 0 )
      printf( "The string \"%s\" is a palindrome\n", string );
   else
      printf( "The string \"%s\" is not a palindrome\n", string );
}

The string "Able was I ere I saw Elba" is a palindrome

See also

String manipulation
Locale
Interpretation of multibyte-character sequences
strcpy, wcscpy, _mbscpy
_strset, _strset_l, _wcsset, _wcsset_l, _mbsset, _mbsset_l