Re: A question regarding C string functions

On Wed, 02 Apr 2025 17:36:22 -0700, Tim Rentsch wrote:

Lew Pitcher <lew.pitcher@digitalfreehold.ca> writes:
 

I cannot find any definitive statement in my copies of the various
C language standards that addresses the behaviour of the C string
functions when given a NULL pointer.
>
Specifically, what does the C standard dictate about the behaviour of
  strrchr(NULL,'/')
but the question could apply to any of the string functions
(strlen(NULL), etc.)
>
My gut impression is that
  strrchr(NULL,'/'), etc
invoke undefined behaviour, and should be avoided.
>
Can anyone comment?

 
There's a general principle when reading the C standard, which
is, when looking at some leaf section, go up the tree and read
the parent section, and also read the grandparent section, and so
on.

[snip]

Incidentally, I learned this principle myself from another helpful
poster (I don't remember who) in comp.lang.c, and am happy to pass
along what has been for me helpful advice.

Many thanks, Tim

I appreciate both yours and Kaz's guidance in this.
I knew that the standard included a caveat here, but, for the life
of me, I couldn't locate it.

I appreciate the assistance; it gives me some measure of confidence
for the changes that I must make to the code that I am revising at
the moment.

Thanks again
--
Lew Pitcher
"In Skills We Trust"