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Redirecting To Dev Null C

 
Expert100+
Hi, all.
I am coding in C on Linux, and using an external library provided by others. This library generates a batch of error/warning messages to stdout, which I do not want to see.
Before each function call to the external library, I can insert the following:
  1. freopen('/dev/null', 'w', stdout);
However, after the function call I cannot figure out how to reroute stdout to the console.
I tried early in the program defining:
  1. FILE *fConsole = stdout;
and then following the function call with
  1. freopen(fConsole, 'w', stdout);
I also tried following the function call with
  1. freopen('CON', 'w', stdout);
Neither worked; all subsequent messages written to stdout continue to go to /dev/null; that is, they disappear.
So.. how do I get the stdout messages back to the console after my external function has executed?
Thanks!
Hi,
Try this idea.
1)Open a file in write mode
2)use dup system call to swap the file descriptor to stdout
3)Open a file in write mode
4)use dup system call to swap the file descriptor to stderr
5)call ur functions/library
6)restore the file descriptor back to stdout and stderr.
7)close the file
u have to use open call instead of fopen for this.
Hope this helps u
Raghuram
Windows dev null

STDERR redirects to THE ADDRESS of STDOUT (File descriptor 1 in that moment, or /proc/self/fd/1), and then STDOUT redirects to /dev/null, but STDERR keeps redirecting to fd1!! As a result the normal output from STDOUT is discarded, but the errors coming from STDERR are still being written onto the console. Apr 08, 2005  On Fri, 08 Apr 2005 07:56:32 -0700, Generic Usenet Account wrote: Dragan Cvetkovic wrote: There is one thing about C-shell that I really like and that is the. Jan 04, 2003  I wonder if this is the right way to redirect stdout, stderr and stdin to /dev/null: SNIP This won't work, all you're doing is redirecting the stdio handles for stdout/err/in, not closing the actually file descriptors. When I examine such program with lsof I can see: redir 25055 trip 0r CHR 1,3 66788 /dev/null.

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Redirect to dev/null c

Pipe To Dev Null

Redirecting to /dev/null won't prevent crashing, but will clean up the stdout and stderr output streams. Tar could cause errors in a variety of ways. You might not have write access, the file might already exist, etc. – Sparhawk Mar 14 '14 at 4:27. Just a trick to avoid unnecessary output. 'it', meaning screen output, doesn't go to /dev/null. First: script records your session (see the manpage), and you don't need it at all: so that goes to /dev/null. But it doesn have a side-effect: it makes a pseudo terminal, and now you are using this, and screen can write to this oneSee @karol-piczak 's anwer.