Solved

C function: mktemp() is not working under linux

Posted on 2014-04-17
7
381 Views
Last Modified: 2014-04-17
I have a c program that used the mktmp function.  It is no longer working since we shifted from HPUX to a Linux environment. I googled and found out that I shouldn't be using mktmp() anymore:
http://man7.org/linux/man-pages/man3/mktemp.3.html

Here is the code, written a long time ago by someone else and my C programming is not sharp (small pun intended):

/* try to create temporary file to hold per-dept recap lines */

    strcpy(recapfilename, "/tmp/tstaff-recap-XXXXXX");
    mktemp(recapfilename);
#ifdef JCCDEBUG
    fprintf(stderr, "%%recap file name is '%s'\n", recapfilename);
#endif /* JCCDEBUG */
    recapfp = fopen(recapfilename, "w+");
    if (recapfp == NULL)
    {
        fprintf(stderr, "%%unable to open recap file '%s'\n", recapfilename);
    }
#ifdef JCCDEBUG
    else
    {
        fprintf(stderr, "%%recap file '%s' opened OK\n", recapfilename);
    }
#endif /* JCCDEBUG */

Can someone give me the new function to use?  When I run the program I get the 'unable to open recap file. So I am sure that is where it is failing when trying to use the mktmp() function.

Thanks in advance!
0
Comment
Question by:dcrowley_01
  • 3
  • 3
7 Comments
 
LVL 5

Assisted Solution

by:Pasha Kravtsov
Pasha Kravtsov earned 250 total points
ID: 40007392
0
 

Author Comment

by:dcrowley_01
ID: 40007406
I changed it to mkstemp() and I get the same error:

unable to open recap file

So it appears the code is ok, but their must be some difference between the environments.
Has anyone ever run into this before?

Can I re-write it so that it doesn't need to write the temp information out to a file and instead holds it in memory or something?
0
 
LVL 5

Expert Comment

by:Pasha Kravtsov
ID: 40007416
Can you copy and paste the error? And mktemp() according to the man pages is a security risk.
0
Back Up Your Microsoft Windows Server®

Back up all your Microsoft Windows Server – on-premises, in remote locations, in private and hybrid clouds. Your entire Windows Server will be backed up in one easy step with patented, block-level disk imaging. We achieve RTOs (recovery time objectives) as low as 15 seconds.

 

Author Comment

by:dcrowley_01
ID: 40007456
The error is: %unable to open recap file ''
0
 
LVL 5

Expert Comment

by:Pasha Kravtsov
ID: 40007465
see if mkstemp() is returning NULL
0
 
LVL 86

Accepted Solution

by:
jkr earned 250 total points
ID: 40007511
Do you (i.e. your account) have permissions to access the directory that holds the temporary files?
0
 

Author Comment

by:dcrowley_01
ID: 40008001
This is not a code problem. Something else is going on with the OS. Going to close the question and split the points.
0

Featured Post

Announcing the Most Valuable Experts of 2016

MVEs are more concerned with the satisfaction of those they help than with the considerable points they can earn. They are the types of people you feel privileged to call colleagues. Join us in honoring this amazing group of Experts.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Attention: This article will no longer be maintained. If you have any questions, please feel free to mail me. jgh@FreeBSD.org Please see http://www.freebsd.org/doc/en_US.ISO8859-1/articles/freebsd-update-server/ for the updated article. It is avail…
This is a short and sweet, but (hopefully) to the point article. There seems to be some fundamental misunderstanding about the function prototype for the "main" function in C and C++, more specifically what type this function should return. I see so…
The goal of this video is to provide viewers with basic examples to understand how to create, access, and change arrays in the C programming language.
This demo shows you how to set up the containerized NetScaler CPX with NetScaler Management and Analytics System in a non-routable Mesos/Marathon environment for use with Micro-Services applications.

749 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question