Find the first substring.
size_t strspn( const char *string, const char *strCharSet );
size_t wcsspn( const wchar_t *string, const wchar_t *strCharSet );
size_t _mbsspn( const unsigned char *string, const unsigned char *strCharSet );
| Routine | Required Header | Compatibility |
| strspn | <string.h> | ANSI, Win 95, Win NT |
| wcsspn | <string.h> or <wchar.h> | ANSI, Win 95, Win NT |
| _mbsspn | <mbstring.h> | Win 95, Win NT |
For additional compatibility information, see Compatibility in the Introduction.
Libraries
| LIBC.LIB | Single thread static library, retail version |
| LIBCMT.LIB | Multithread static library, retail version |
| MSVCRT.LIB | Import library for MSVCRT.DLL, retail version |
Return Value
strspn, wcsspn, and _mbsspn return an integer value specifying the length of the substring in string that consists entirely of characters in strCharSet. If string begins with a character not in strCharSet, the function returns 0. No return value is reserved to indicate an error. For each of these routines, no return value is reserved to indicate an error.
Parameters
string
Null-terminated string to search
strCharSet
Null-terminated character set
Remarks
The strspn function returns the index of the first character in string that does not belong to the set of characters in strCharSet. The search does not include terminating null characters.
wcsspn and _mbsspn are wide-character and multibyte-character versions of strspn. The arguments of wcsspn are wide-character strings; those of _mbsspn are multibyte-character strings. These three functions behave identically otherwise.
Generic-Text Routine Mappings
| TCHAR.H Routine | _UNICODE & _MBCS Not Defined | _MBCS Defined | _UNICODE Defined |
| _tcsspn | strspn | _mbsspn | wcsspn |
Example
/* STRSPN.C: This program uses strspn to determine
* the length of the segment in the string "cabbage"
* consisting of a's, b's, and c's. In other words,
* it finds the first non-abc letter.
*/
#include <string.h>
#include <stdio.h>
void main( void )
{
char string[] = "cabbage";
int result;
result = strspn( string, "abc" );
printf( "The portion of '%s' containing only a, b, or c "
"is %d bytes long\n", string, result );
}
Output
The portion of 'cabbage' containing only a, b, or c is 5 bytes long
See Also _mbsspnp, strcspn, strncat, strncmp, strncpy, _strnicmp, strrchr