char * strchrnul

char * strchrnul(const char *, int) __ATTR_PURE__

The strchrnul() function is like strchr() except that if c is not found in s, then it returns a pointer to the null byte at the end of s, rather than NULL. (Glibc, GNU extension.)

Remember:

The strchrnul() function returns a pointer to the matched character, or a pointer to the null byte at the end of s (i.e., s+strlen(s)) if the character is not found.