What is strcmp supposed to return if one or both arguments passed to it are NULL ?

spibou

What is strcmp supposed to return if one or both arguments passed to it
are NULL ?

Jul 13 '06 #1

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2209

Richard Heathfield

sp****@gmail.co m said:

What is strcmp supposed to return if one or both arguments passed to it
are NULL ?

A demon.

Inspect your handkerchief - carefully.

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at above domain (but drop the www, obviously)

Jul 13 '06 #2

Chris Dollin

sp****@gmail.co m wrote:

What is strcmp supposed to return if one or both arguments passed to it
are NULL ?

It isn't.

If either argument to strcmp is null, the behaviour is undefined.

So it may return -1, or 1, or 0, or 17, or 1829. It may generate some
kind of signal. It may exit, increment arbitrary memory, or call
some random one of your functions. Anything: the C standard places
no restrictions on strcmp if either argument is null; there is no
"supposed".

Typically, the behaviour is constrained by other standards and
mechanisms obeyed and performed by your implementation, so you'd
better hope that /they/ are working for you.

Are you willing to bet your nose on it?

--
Chris "one nostril at a time" Dollin
"I'm still here and I'm holding the answers" - Karnataka, /Love and Affection/

Jul 13 '06 #3

lovecreatesbeauty

sp****@gmail.co m wrote:

What is strcmp supposed to return if one or both arguments passed to it
are NULL ?

It may not be completed and crash midway, thereby having nothing
returned.

lovecreatesbeau ty

Jul 13 '06 #4

goose

sp****@gmail.co m wrote:

What is strcmp supposed to return if one or both arguments passed to it
are NULL ?

Why don't you try it and let us know?

Or read a good C book?
Or read the FAQ for this group (posted everywhere)
Or read the standards document?

....

Or simply tell your instructor that you're
too lazy to be doing this course?

goose,
bad bad bad!!! I *really* should be more
mild on the newsgroups, but sometimes I just
cannot help myself.

Jul 13 '06 #5

Keith Thompson

"goose" <ru**@webmail.c o.zawrites:

sp****@gmail.co m wrote:
>What is strcmp supposed to return if one or both arguments passed to it
are NULL ?

Why don't you try it and let us know?

Perhaps because trying it won't actually answer the question.

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <* <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

Jul 13 '06 #6

goose

Keith Thompson wrote:

"goose" <ru**@webmail.c o.zawrites:
sp****@gmail.co m wrote:
What is strcmp supposed to return if one or both arguments passed to it
are NULL ?
Why don't you try it and let us know?

Perhaps because trying it won't actually answer the question.

This is turning out to be an embarrassingly bad day for me

goose,

Jul 13 '06 #7

Keith Thompson

"goose" <ru**@webmail.c o.zawrites:

Keith Thompson wrote:
>"goose" <ru**@webmail.c o.zawrites:
sp****@gmail.co m wrote:
What is strcmp supposed to return if one or both arguments passed to it
are NULL ?

Why don't you try it and let us know?

Perhaps because trying it won't actually answer the question.

This is turning out to be an embarrassingly bad day for me

We all have them.

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <* <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

Jul 13 '06 #8

spibou

goose wrote:

sp****@gmail.co m wrote:
What is strcmp supposed to return if one or both arguments passed to it
are NULL ?
Or read the standards document?

I read the Standard. It didn't say.

Jul 13 '06 #9

Andrew Poelstra

On 2006-07-13, sp****@gmail.co m <sp****@gmail.c omwrote:

>
goose wrote:

>sp****@gmail.co m wrote:
What is strcmp supposed to return if one or both arguments passed to it
are NULL ?
Or read the standards document?

I read the Standard. It didn't say.

The Standard does say that if the Standard doesn't define something, it
is undefined.

Therefore, this is undefined.

--
Andrew Poelstra <http://www.wpsoftware. net/projects/>
To email me, use "apoelstra" at the above domain.
"You people hate mathematics." -- James Harris

Jul 13 '06 #10

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