memchr

locate character in block of memory

strchr

finds a specified character in a string

strcspn

returns the length of the initial part of a string that does not contain specified characters

strpbrk 

locate first character from character set

strrchr

find last copy of specified character in string

strspn

returns the length of the initial part of a string that contains specified characters

strstr

locate substring within string

strtok

returns a pointer to the first character of a token