STRCSPN(3) BSD Programmer's Manual STRCSPN(3)
strcspn - span the complement of a string
#include <string.h> size_t strcspn(const char *s, const char *charset);
The strcspn() function spans the initial part of the NUL-terminated string s as long as the characters from s do not occur in string charset (it spans the complement of charset).
The strcspn() function returns the number of characters spanned.
The following call to strcspn() will return 3, since the first three characters of string s do not occur in string charset: char *s = "foobar"; char *charset = "bar"; size_t span; span = strcspn(s, charset);
memchr(3), strchr(3), strpbrk(3), strrchr(3), strsep(3), strspn(3), strstr(3), strtok(3)
The strcspn() function conforms to ANSI X3.159-1989 ("ANSI C89"). MirBSD #10-current June 29, 1991 1