Redirection does not appear to be supported

[kevinboone]

There doesn't seem to be a way to redirect stdin/stdout/stderr to a file. dup/dup2 fail at link time -- presumably there is not implementation. freopen ("foo.txt", "w", stdout) appears to work, and no further output is produced to the console. But, so far as I can tell, nothing is written to the file, either.

This is a nuisance for me because I have a number of large libraries that write to stdout, and I need them to process their output in my code. On Linux, I just redirect the output, run the library, and then read back the file. I can't see a way to do this using circle-stdlib.

While it would be nice if dup/dup2 worked, for my purposes I would be perfectly happy to use circle-specific APIs to do the redirection.

[smuehlst]

I'm sorry, this is one of the known gaps, and I currently am not investing much time into circle-stdlib. There are some more newly implemented functions already waiting on the develop branch, which I will probably release in the near future, but dup() and fcntl() are not among them.

[smuehlst]

@kevinboone It was less effort than I thought. dup(), dup2() and the duplication-related functionality of fcntl() are now implemented on the develop branch as of commit 25aab9c357e5f01a2b8ccb2993bc619e34167944. Please give it a try and let me know whether it works for you.

[kevinboone]

Hi. Thanks for this. I'm away from my desk at present, but I'm keen to try this, and the chdir/getcwd fix, as soon as I can. Now, I hope you'll pardon my lack of knowledge of GitHub -- if I check out the 'develop' branch of circle-stdlib, will I get the 'develop' branch of Circle as well? Or do I need to check that out separately? If you don't have time to answer this, don't worry -- I'll figure it out by trial-and-error ;)

[smuehlst]

The following should work from the root directory of the circle-stdlib repository:

git checkout develop
git submodule update --init --recursive

Then proceed with the normal configure and make procedure.

[smuehlst]

circle-stdlib v16 has been released where dup() and dup2() have been implemented.

[kevinboone]

Thank you for implementing this. For the record, I can now redirect stdout by doing something like this:

int fd = open ("foo.txt", O_WRONLY | O_TRUNC | O_CREA); int stdout_copy = dup (1); dup2 (fd, 1); // Do something... fflush (stdout); dup2 (stdout_copy, 1); close (stdout_copy); close (fd);

[smuehlst]

You're welcome. Also redirection via freopen() does work now.