strspn

size_t strspn( const char *dest, const char *src );

Returns the length of the maximum initial segment (span) of the null-terminated byte string pointed to by dest, that consists of only the characters found in the null-terminated byte string pointed to by src.

The behavior is undefined if either dest or src is not a pointer to a null-terminated byte string.

Parameters

Return value

The length of the maximum initial segment that contains only characters from the null-terminated byte string pointed to by src.

Example

#include <string.h>
#include <stdio.h>
 
int main(void)
{
    const char *string = "abcde312$#@";
    const char *low_alpha = "qwertyuiopasdfghjklzxcvbnm";
 
    size_t spnsz = strspn(string, low_alpha);
    printf("After skipping initial lowercase letters from '%s'\n"
           "The remainder is '%s'\n", string, string+spnsz);
}

After skipping initial lowercase letters from 'abcde312$#@'
The remainder is '312$#@'

References

• C11 standard (ISO/IEC 9899:2011):
• 7.24.5.6 The strspn function (p: 369)
• C99 standard (ISO/IEC 9899:1999):
• 7.21.5.6 The strspn function (p: 332)
• C89/C90 standard (ISO/IEC 9899:1990):
• 4.11.5.6 The strspn function

See also