STRSPN

strspn, strcspn − search a string for a set of characters

#include <string.h>

size_t strspn(const char *s, const char *accept);

size_t strcspn(const char *s, const char *reject);

The strspn() function calculates the length of the initial segment of s which consists entirely of characters in accept.

The strcspn() function calculates the length of the initial segment of s which consists entirely of characters not in reject.

The strspn() function returns the number of characters in the initial segment of s which consist only of characters from accept.

The strcspn() function returns the number of characters in the initial segment of s which are not in the string reject.

SVID 3, POSIX, BSD 4.3, ISO 9899

index(3), memchr(3), rindex(3), strchr(3), strpbrk(3), strsep(3), strstr(3), strtok(3)