Re: xstring.h

[Bruno Haible]

Eric Blake wrote:
> |   /* Return a substring of the given string, len bytes long starting at
> str.  */
> |   char * xsubstring (const char *str, size_t len);
> 
> How is this different from [x]strndup?  At least strndup is standardized.

For xsubstring, the caller guarantees that the len bytes are not NUL; the
function then returns a string of length == len.

strndup is a glibc (not POSIX) function. I find the semantics of strndup,
strnlen, and strncmp always hard to remember. This complexity is not needed
here: When you are extracting a substring, you already know that the string
does not end before (str + len).

Bruno