strcspn, wcscspn, _mbscspn, _mbscspn_l

Returns the index of the first occurrence in a string, of a character that belongs to a set of characters.


_mbschr and _mbschr_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.


size_t strcspn(
   const char *str,
   const char *strCharSet
size_t wcscspn(
   const wchar_t *str,
   const wchar_t *strCharSet
size_t _mbscspn(
   const unsigned char *str,
   const unsigned char *strCharSet
size_t _mbscspn_l(
   const unsigned char *str,
   const unsigned char *strCharSet,
   _locale_t locale


Null-terminated searched string.

Null-terminated character set.

Locale to use.

Return value

These functions return the index of the first character in str that is in strCharSet. If none of the characters in str is in strCharSet, then the return value is the length of str.

No return value is reserved to indicate an error.


wcscspn and _mbscspn are wide-character and multibyte-character versions of strcspn. The arguments of wcscspn are wide-character strings. The arguments and return value of _mbscspn are multibyte-character strings.

_mbscspn validates its parameters. If either str or strCharSet is a null pointer, the invalid parameter handler is invoked, as described in Parameter validation. If execution is allowed to continue, the function returns 0 and sets errno to EINVAL. strcspn and wcscspn don't validate their parameters. These three functions behave identically otherwise.

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 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.

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
_tcscspn strcspn _mbscspn wcscspn


Routine Required header
strcspn <string.h>
wcscspn <string.h> or <wchar.h>
_mbscspn, _mbscspn_l <mbstring.h>

For more compatibility information, see Compatibility.


// crt_strcspn.c

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

void test( const char * str, const char * strCharSet )
   int pos = strcspn( str, strCharSet );
   printf( "strcspn( \"%s\", \"%s\" ) = %d\n", str, strCharSet, pos );

int main( void )
   test( "xyzbxz", "abc" );
   test( "xyzbxz", "xyz" );
   test( "xyzbxz", "no match" );
   test( "xyzbxz", "" );
   test( "", "abc" );
   test( "", "" );
strcspn( "xyzbxz", "abc" ) = 3
strcspn( "xyzbxz", "xyz" ) = 0
strcspn( "xyzbxz", "no match" ) = 6
strcspn( "xyzbxz", "" ) = 6
strcspn( "", "abc" ) = 0
strcspn( "", "" ) = 0

See also

String manipulation
Interpretation of multibyte-character sequences
strncat, _strncat_l, wcsncat, _wcsncat_l, _mbsncat, _mbsncat_l
strncmp, wcsncmp, _mbsncmp, _mbsncmp_l
strncpy, _strncpy_l, wcsncpy, _wcsncpy_l, _mbsncpy, _mbsncpy_l
_strnicmp, _wcsnicmp, _mbsnicmp, _strnicmp_l, _wcsnicmp_l, _mbsnicmp_l
strrchr, wcsrchr, _mbsrchr, _mbsrchr_l
strspn, wcsspn, _mbsspn, _mbsspn_l