Hi, in the section return value, strchr(3) and strrchr(3) explicitly state the behaviour for NUL: <https://man7.org/linux/man-pages/man3/strstr.3.html#RETURN_VALUE> <https://man7.org/linux/man-pages/man3/strrchr.3.html#RETURN_VALUE> | The terminating null byte is considered part of the string, so | that if c is specified as '\0', these functions return a pointer | to the terminator. JFTR: to avoid any possible confusion of "null byte" alias NUL with the "null pointer" alias NULL (C macro) or nullptr (C++), "null byte" should be replaced with "NUL byte"! The same explicit statement is but missing from both <https://man7.org/linux/man-pages/man3/wcschr.3.html#RETURN_VALUE> and <https://man7.org/linux/man-pages/man3/wcsrchr.3.html#RETURN_VALUE> and should be added there. regards Stefan