Re: Temporarily close stdout?

In article <42aa5189-6a17-41d9-9528-4c1361d99170@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
Joakim Hove <joakim.hove@xxxxxxxxx> wrote:

/* Temporarily redirect stdout -> /dev/null */
stdout = freopen("/dev/null" , "w" , stdout);

Don't assign the result to stdout. freopen() changes stdout itself.

/* restore stdout */
stdout = freopen("/dev/stdout" , "w" , stdout);

But - the last freopen() fails with 2:No such file or directory.

Probably it closes stdout before trying to open /dev/stdout.

The dup() approach with /dev/fd would be something like (not tested):

char buf[20];
int saved_stdout = dup(1);

freopen("/dev/null", "w", stdout);
lsb_submit( &request , &reply );
sprintf(buf, "/dev/fd/%d", saved_stdout);
freopen(buf, "w", stdout);

To avoid dup(), but still relying on /dev/stdout, do

FILE *mystdout = fopen("/dev/stdout", w);
freopen("/dev/null", "w", stdout);

and change your code to write to write to mystdout instead of stdout.

You'd be wise to ask in a unix, linux or posix newsgroup, because
there may be subtleties to the workings of /dev/stdout and /dev/fd/.

-- Richard
--
:wq
.

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