How to redirect stdout on Atari?

[RA_pdx]

Hi,

I want to redirect stdout to a log file and write with printf to this file.

How can i do this on an Atari machine?

I have tried to use Gemdos functions Fforce and Fdup but with no success. Text was not anymore on screen but also not in my created file (it is created but empty).

Code: Select all

FILE*	pFile;
pFile = fopen(strFile, "w");
	
if (pFile == NULL){
	return false;
}
	
Fforce(1, Fdup(fileno(pFile)));

printf("Test");
	
fclose(pFile);

[m0n0]

With mintlib it's easy (don't know about PureC lib, or AHCC...., but you can look at the mintlib source to see if you can implement it for yourself):


freopen("stdout.log", "a+", stdout);
freopen("stderr.log", "a+", stderr);

eventually you want to disable output buffering:
setbuf(stderr, NULL);
setbuf(stdout, NULL);

now you can printf to stdout / stderr and it will be written to the file....

[BlankVector]

m0n0's answer is the right one.

BTW:

Code: Select all

Fforce(1, Fdup(fileno(pFile)));

You should remove Fdup() there.
http://toshyp.atari.org/en/005009.html#Fdup
http://toshyp.atari.org/en/005009.html#Fforce

[RA_pdx]

I have already tried it without Fdup but both versions didn´t work.

Thanks, i will have a look on the source of mintlib.
Even i had the hope that there is an easy way with TOS.

[BlankVector]

I have already tried it without Fdup but both versions didn´t work.

Do you use Hatari with GEMDOS hard disk emulation?
Redirection does not seem to work in that case. The result is always an empty file.
However, if the redirected file is located on the floppy, it works as expected.

[wongck]

This works for me, compiled under Pure C.

Code: Select all

#include <tos.h>
#include <stdio.h>

void main(void)
{
  long fno;
  
  fno = Fcreate("myoutput.txt", 0);
  Fforce( 1, (long) fno);    /* redirect screen to file */
  printf("hello world");
  Fclose(fno);
  
} 

hello world goes into the file called myoutput.txt.
So may be it is Hatari like what Vincent said.

[RA_pdx]

I have already tried it without Fdup but both versions didn´t work.

Do you use Hatari with GEMDOS hard disk emulation?
Redirection does not seem to work in that case. The result is always an empty file.
However, if the redirected file is located on the floppy, it works as expected.

Yes thanks, you are right. I am using Hatari with GEMDOS hard disk.
Now i know that it was not my fault that it doesn´t work - i spent several hours on this problem...

Thanks to everybody for your help!

[Eero Tamminen]

Yes thanks, you are right. I am using Hatari with GEMDOS hard disk.
Now i know that it was not my fault that it doesn´t work - i spent several hours on this problem...

When having problems with OS calls, it helps to check their return values. TOS should be returning "invalid handle" error in this case.

The reason why Fforce() isn't implemented is that Hatari GEMDOS emulation doesn't (currently) have any knowledge of programs, it just catches GEMDOS calls.

Implications of this mean some differences to TOS:
* GEMDOS emulation file handles are global to the whole system, not specific to the program.
Other programs can access them if they just use correct handle (GEMDOS emulation handle IDs start from 64).
* Files that program leaves open aren't closed on program termination like TOS does.
I.e. GEMDOS emulated file handles could run out if exiting programs leave them open (unlike with TOS).
* Forced file handles wouldn't be automatically un-redirected on program exit (when it forgets to close it).
This which would be pretty much catastrophe.

I'm looking whether these could be worked around for next Hatari version.

[RA_pdx]

I'm looking whether these could be worked around for next Hatari version.

That would be great

[Eero Tamminen]

I'm looking whether these could be worked around for next Hatari version.

That would be great

I've looked now into that and I don't think it's possible. There doesn't seem to be any reliable way to catch all the possible ways of program starting (GEMDOS pexec, AES shel_write etc) and terminating (3 Pterm functions, crashing etc) so that GEMDOS emulation current program information would be reliably in sync with TOS.

If you're sure that all your programs close files they Fforced, I've mailed a patch to hatari-devel mailing list to get Fforce() files redirected under GEMDOS emulation. It's not something that can be put into release though, as redirections are removed only when Fclose is called on related handle (not on program termination).

To release I'll probably add just console warnings when trying to Fforce() GEMDOS emulated files and when files are left open at Pterm*().

[Eero Tamminen]

I'll probably add just console warnings when trying to Fforce() GEMDOS emulated files and when files are left open at Pterm*().

I've commited that to Mercurial and added notes about this to GEMDOS emulation section in Hatari manual:
http://hg.tuxfamily.org/mercurialroot/h ... _emulation

I'd recommend reading the documentation on that, Fforce() & file closing on program termination are not the only issues for GEMDOS HD emulation...

[RA_pdx]

I always close all opened files so that´s no problem.
It´s a good workaround for me. Thanks Eero.

[Eero Tamminen]

I always close all opened files so that´s no problem.
It´s a good workaround for me. Thanks Eero.

Note that even when using GEMDOS emulation (without the attached fforce.diff against Hatari Mercurial tip [1]), any files that reside on floppy or HD images can still be redirected as those are forwarded to TOS.

[1] http://hg.tuxfamily.org/mercurialroot/h ... i/shortlog

[Eero Tamminen]

I think I found a way to do redirecting so that it's safe (gets unredirected when needed). Code to do that is commited to Hatari repository.

Hatari will now also tell about how many file handles were left open / re-directed when program terminates normally (through Pterm*()).

[RA_pdx]

Great news, thanks again.