From ddjolley at gmail.com  Sun Nov 20 12:11:03 2005
From: ddjolley at gmail.com (Doug Jolley)
Date: Sun, 20 Nov 2005 12:11:03 -0800
Subject: [OCLUG-devel] fopen doesn't like my path
Message-ID: <b31d342a0511201211u44272200qcc5d9e771dba1f90@mail.gmail.com>

I am using fopen to open two different files. In the first case (which works
just fine), I simply define the path to the file as 'char
path2file[]="/path/to/file"'. I then use path2file as the first argument to
fopen. In the second case (which doesn't work so well), I extract the path
to the file from colon-delimited data contained in a string using strtok.
IOW, I use the following 'path=strtok(NULL,":")'. I use NULL here because I
have previously extracted other tokens and the path is the next token to be
extracted. I inserted a printf statement to print 'path' and it does in fact
point to the correct data. However, when I put 'path' as the first argument
to fopen, I get a segmentation fault. If I replace the 'path' argument to
fopen with the actual correct path to the file (by just including the actual
string enclosed in double quotes), it works just fine. So, it certainly
appears that fopen doesn't like my path pointer which was derived from
strtok; but, I have absolutely no idea why. Can anyone help me out? Thanks
for any input.

... doug
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://localhost.localdomain/pipermail/oclug-devel/attachments/20051120/3ec68cff/attachment.html 

From michael.elkins at gmail.com  Sun Nov 20 18:28:33 2005
From: michael.elkins at gmail.com (Michael Elkins)
Date: Sun, 20 Nov 2005 18:28:33 -0800
Subject: [OCLUG-devel] fopen doesn't like my path
In-Reply-To: <b31d342a0511201211u44272200qcc5d9e771dba1f90@mail.gmail.com>
References: <b31d342a0511201211u44272200qcc5d9e771dba1f90@mail.gmail.com>
Message-ID: <404f03220511201828x40b1d88bnc0a88776928dca7d@mail.gmail.com>

You'll likely need to post the code snippet your using in order for us
to determine what the exact issue is.  Nothing in your description
seems incorrect.

Michael

On 11/20/05, Doug Jolley <ddjolley at gmail.com> wrote:
> I am using fopen to open two different files.  In the first case (which
> works just fine), I simply define the path to the file as 'char
> path2file[]="/path/to/file"'.  I then use path2file as the first argument to
> fopen.  In the second case (which doesn't work so well), I extract the path
> to the file from colon-delimited data contained in a string using strtok.
> IOW, I use the  following 'path=strtok(NULL,":")'.  I use NULL here because
> I have previously extracted other tokens and the path is the next token to
> be extracted.  I inserted a printf statement to print 'path' and it does in
> fact point to the correct data.  However, when I put 'path' as the first
> argument to fopen, I get a segmentation fault.  If I replace the 'path'
> argument to fopen with the actual correct path to the file (by just
> including the actual string enclosed in double quotes), it works just fine.
> So, it certainly appears that fopen doesn't like my path pointer which was
> derived from strtok; but, I have absolutely no idea why.  Can anyone help me
> out?  Thanks for any input.
>
>          ... doug
>
> _______________________________________________
> OCLUG-devel mailing list -- OCLUG-devel at oclug.org
> http://mailman.oclug.org/mailman/listinfo/oclug-devel
>
>
>

From ddjolley at gmail.com  Sun Nov 20 20:29:53 2005
From: ddjolley at gmail.com (Doug Jolley)
Date: Sun, 20 Nov 2005 20:29:53 -0800
Subject: [OCLUG-devel] fopen doesn't like my path
In-Reply-To: <404f03220511201828x40b1d88bnc0a88776928dca7d@mail.gmail.com>
References: <b31d342a0511201211u44272200qcc5d9e771dba1f90@mail.gmail.com>
	 <404f03220511201828x40b1d88bnc0a88776928dca7d@mail.gmail.com>
Message-ID: <b31d342a0511202029m2f69c3c8qcd7491e52493404d@mail.gmail.com>

Hi, Michael. Thanks for responding. I got it figured out. It turns out
(apparently) that when one extracts a token from a string using strtok a
newline character is appended to the token. It was the trailing newline
character in the path token that fopen didn't like (as it shouldn't). Once I
chopped it off everything worked just fine. It did have me going for quite a
while though.

Thanks again for the response.

... doug
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://localhost.localdomain/pipermail/oclug-devel/attachments/20051120/bf1f5e7d/attachment.html 

From x at xman.org  Sun Nov 20 21:28:59 2005
From: x at xman.org (Christopher Smith)
Date: Sun, 20 Nov 2005 21:28:59 -0800
Subject: [OCLUG-devel] fopen doesn't like my path
In-Reply-To: <b31d342a0511201211u44272200qcc5d9e771dba1f90@mail.gmail.com>
References: <b31d342a0511201211u44272200qcc5d9e771dba1f90@mail.gmail.com>
Message-ID: <43815B1B.8020401@xman.org>

Doug Jolley wrote:

> I am using fopen to open two different files.  In the first case 
> (which works just fine), I simply define the path to the file as 'char 
> path2file[]="/path/to/file"'.  I then use path2file as the first 
> argument to fopen.  In the second case (which doesn't work so well), I 
> extract the path to the file from colon-delimited data contained in a 
> string using strtok.  IOW, I use the  following 
> 'path=strtok(NULL,":")'.  I use NULL here because I have previously 
> extracted other tokens and the path is the next token to be 
> extracted.  I inserted a printf statement to print 'path' and it does 
> in fact point to the correct data.  However, when I put 'path' as the 
> first argument to fopen, I get a segmentation fault.  If I replace the 
> 'path' argument to fopen with the actual correct path to the file (by 
> just including the actual string enclosed in double quotes), it works 
> just fine.  So, it certainly appears that fopen doesn't like my path 
> pointer which was derived from strtok; but, I have absolutely no idea 
> why.  Can anyone help me out?  Thanks for any input.

At first glance, it sounds like it *should* be working. Perhaps you 
could post a code sample that demonstrates your problem? I find it a 
helpful excercise to come up with a code sample for these kinds of 
problens, because often the problem goes away after you've removed what 
you think are irrelevant bits of code. If the problem is still there, 
then you have a concise way of describing it.

--Chris

From x at xman.org  Sun Nov 20 21:34:44 2005
From: x at xman.org (Christopher Smith)
Date: Sun, 20 Nov 2005 21:34:44 -0800
Subject: [OCLUG-devel] fopen doesn't like my path
In-Reply-To: <b31d342a0511202029m2f69c3c8qcd7491e52493404d@mail.gmail.com>
References: <b31d342a0511201211u44272200qcc5d9e771dba1f90@mail.gmail.com>
	<404f03220511201828x40b1d88bnc0a88776928dca7d@mail.gmail.com>
	<b31d342a0511202029m2f69c3c8qcd7491e52493404d@mail.gmail.com>
Message-ID: <43815C74.9020709@xman.org>

Doug Jolley wrote:

> Hi, Michael.  Thanks for responding.  I got it figured out.  It turns 
> out (apparently) that when one extracts a token from a string using 
> strtok a newline character is appended to the token.  It was the 
> trailing newline character in the path token that fopen didn't like 
> (as it shouldn't).  Once I chopped it off everything worked just 
> fine.  It did have me going for quite a while though.

Hehe, just got your post and Michael's. ;-)

strtok shouldn't be inserting a trailing newline anywhere. The only 
character it inserts is a NULL (which replaces the delimiter). Are you 
sure something else wasn't inserting the newline (or for that matter, 
the newline might have already been there)?

--Chris

From ddjolley at gmail.com  Mon Nov 21 09:30:35 2005
From: ddjolley at gmail.com (Doug Jolley)
Date: Mon, 21 Nov 2005 09:30:35 -0800
Subject: [OCLUG-devel] fopen doesn't like my path
In-Reply-To: <43815C74.9020709@xman.org>
References: <b31d342a0511201211u44272200qcc5d9e771dba1f90@mail.gmail.com>
	 <404f03220511201828x40b1d88bnc0a88776928dca7d@mail.gmail.com>
	 <b31d342a0511202029m2f69c3c8qcd7491e52493404d@mail.gmail.com>
	 <43815C74.9020709@xman.org>
Message-ID: <b31d342a0511210930x57f482b4x89ef91f047598650@mail.gmail.com>

>
> (or for that matter,
> the newline might have already been there)?
>

Chris, I think that was probably the case. The string that strtok was
parsing came from a data file. In this case the datafile was a text file
with colon delimited fields and newline delimited records. Guess what? The
particular field in question was the last field in the record therefore it
was followed by a newline character.

It occurs to me (now that I better understand this) that rather than
chopping off the trailing newline character what I should have done as the
fix was include a newline in the strtok delimiters.

Thanks for pointing out the error of my ways because I probably would have
gone away with the misconception that strtok appends a newline character and
that would have probably caused me additional problems in the future.

... doug
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://localhost.localdomain/pipermail/oclug-devel/attachments/20051121/92b597ef/attachment.html