strcspn(9) centos man page | unix.com

STRCSPN(9)						     Basic C Library Functions							STRCSPN(9)

NAME
       strcspn - Calculate the length of the initial substring of s which does not contain letters in reject

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

ARGUMENTS
       s
	   The string to be searched

       reject
	   The string to avoid

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014								STRCSPN(9)