_strrev, _wcsrev, _mbsrev, _mbsrev_l

Reverse characters of a string.

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 


  • 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.


The _strrev function reverses the order of the characters in string. 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; those of _mbsrev are multibyte-character strings. For _mbsrev, the order of bytes in each multibyte character in string is not 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 do not validate their parameters.

The output value is affected by the setting of the LC_CTYPE category setting of the locale; see setlocale for more information. The versions of these functions without the _l suffix use the current locale for this locale-dependent behavior; the versions with the _l suffix are identical except that they use the locale parameter passed in instead. For more information, see Locale.

Security Note    These functions incur a potential threat brought about by a buffer overrun problem. Buffer overrun problems are a frequent method of system attack, resulting in an unwarranted elevation of privilege. For more information, see Avoiding Buffer Overruns.

Generic-Text Routine Mappings

TCHAR.H routine

_UNICODE & _MBCS not defined

_MBCS defined

_UNICODE defined











Required header




<string.h> or <wchar.h>

_mbsrev, _mbsrev_l


For additional compatibility information, see Compatibility in the Introduction.


// 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 );
      printf( "The string \"%s\" is not a palindrome\n", string );
The string "Able was I ere I saw Elba" is a palindrome

.NET Framework Equivalent

Not applicable. To call the standard C function, use PInvoke. For more information, see Platform Invoke Examples.

See Also


String Manipulation (CRT)


Interpretation of Multibyte-Character Sequences

strcpy, wcscpy, _mbscpy

_strset, _strset_l, _wcsset, _wcsset_l, _mbsset, _mbsset_l