strtok() - string tokens
#include <string.h>
char * strtok (char *str, const char *sep)
The strtok(3) function is used to isolate sequential tokens in a null-terminated string, str. These tokens are separated in the string by at least one of the characters in sep. The first time that strtok(3) is called, str should be specified; subsequent calls, wishing to obtain further tokens from the same string, should pass a null pointer instead. The separator string, sep, must be supplied each time, and may change between calls.
The strtok(3) function returns a pointer to the beginning of each subsequent token in the string, after replacing the token itself with a NUL character. When no more tokens remain, a null pointer is returned.
memchr(3)
strchr(3)
strcspn(3)
strpbrk(3)
strrchr(3)
strsep(3)
strspn(3)
strstr(3)