From:	"Ben Davis" <ben AT vjpoole DOT freeserve DOT co DOT uk>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Possible bug in libc tmpnam() function
Date:	Fri, 14 Sep 2001 11:38:20 +0100
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Hmm, now I don't know what to think. fopen(outfile, "wt") had the same
effect - errno was set to ENOENT. Is this correct behaviour then?

Thank you again,

Ben Davis
http://bdavis.netfirms.com/

> Hi,
>
> I wrote a program which reads a large quantity of data from one file and
> then writes data to another. The output file is chosen using the tmpnam()
> function, to be renamed at the end. It is most convenient for me to detect
> errors by checking if errno is nonzero once at the end of the program. To
my
> dismay, I found ENOENT in the variable by the time my program had
finished -
> and this is after the input file had been opened, since an error at that
> point would have been output with a different message.
>
> A quick debugging session showed that tmpnam() changed the value of errno,
> yet it filled the string with a valid filename which was later opened
> successfully. I would presume errno was set when testing for the presence
of
> the file, since tmpnam() does not overwrite existing files. However, it is
> my understanding that errno should be preserved by all successful library
> calls.
>
> I must admit I am using an old version of DJGPP. However, on the off
chance
> that the bug has not yet been fixed, I thought it best to tell you.
>
> Thank you,
>
> Ben Davis
> http://bdavis.netfirms.com/

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