Two Questions about "strlen", "strcat" and "strcpy"

[Brian Inglis]

No, NULL doesn't denote a string, and even if it did,
a length of -1 would "make sense" only if it pertained
to going backward from the given starting location.

It could also refer to the character before the end of string.

 

[Richard Bos]

It could also refer to the character before the end of string.

Not as a return value from strlen(), it doesn't. And besides, C != Icon.

Richard

 

[Douglas A. Gwyn]

It could also refer to the character before the end of string.

I suppose almost any arbitrary meaning could be assigned
to meaningless cases. However, strlen can't return a
negative value for any valid string, at least not while
preserving its traditional behavior.