Feature Requests item #1324176, was opened at 2005-10-11 21:46
Message generated for change (Comment added) made by loewis
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Category: Windows
Group: None
>Status: Closed
>Resolution: Works For Me
Priority: 5
Submitted By: Vambola Kotkas (kotk)
Assigned to: Nobody/Anonymous (nobody)
Summary: fix for ms stdio tables
Initial Comment:
Hopefully its right tracker for such request.
I am mainly C++ developer but recently it become
desirable to embed python as python24.dll into my
existing app to make some of features scriptable. I don't
want it to have any visible UI or to deal with GUI or the
like.
However ms has made it so that each dll has its own rtl
ioinfo table that is loaded at program start. In other
words .. some other dll or exe itself cannot simply
redirect python24.dll stdin stdout stderr runtime. It
probably has to be done from within python for these
redirections to really take effect. I think it is actually very
simple to fix that dll problem on C level by making some
callable thing into python24.dll that does nothing but
fixes dlls ioinfo table to contain real stdio for the
process. Example:
#include <windows.h>
#include <io.h>
void Py_FixMSstdioPITA(void)
{
/*fix stdin*/
HANDLE hReal = GetStdHandle
(STD_INPUT_HANDLE);
HANDLE hKnown = _get_osfhandle(_fileno
(stdin));
int Number;
if (hReal != hKnown && hReal !=
INVALID_HANDLE_VALUE)
{
Number = _open_osfhandle
(hReal, _O_BINARY|_O_RDONLY);
_dup2(Number,_fileno(stdin));
}
/*fix stdout*/
hReal = GetStdHandle
(STD_OUTPUT_HANDLE);
hKnown = _get_osfhandle(_fileno(stdout));
if (hReal != hKnown && hReal !=
INVALID_HANDLE_VALUE)
{
Number = _open_osfhandle
(hReal, _O_BINARY|_O_WRONLY);
_dup2(Number,_fileno(stdout));
}
/*fix stderr*/
hReal = GetStdHandle
(STD_ERROR_HANDLE);
hKnown = _get_osfhandle(_fileno(stderr));
if (hReal != hKnown && hReal !=
INVALID_HANDLE_VALUE)
{
Number = _open_osfhandle
(hReal, _O_BINARY|_O_WRONLY);
_dup2(Number,_fileno(stderr));
}
}
I want just call it from outside after any io redirection
done in my code ... so python has his stdio all right and
done.
If something like this is already implemented there in
similar or some other way then sorry didnt find it. If its
agains general python ideology of some sort then sorry
didnt know of it. Let me know please.
Best wishes,
Vambola Kotkas
----------------------------------------------------------------------
>Comment By: Martin v. Löwis (loewis)
Date: 2005-11-09 06:28
Message:
Logged In: YES
user_id=21627
It normally shouldn't happen that you get two copies of
msvcr71.dll. To analyse this problem, you should look at
your application in depends.exe; if it shows different
versions of the CRT, you lose. In your case, it would have
shown both msvcr71.dll and msvcr71d.dll, each having its own
notion of stdio.
Never ever mix different CRT versions. It will not only not
work; it may even crash.
Closing this as "works for me".
----------------------------------------------------------------------
Comment By: Vambola Kotkas (kotk)
Date: 2005-11-09 04:12
Message:
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Right, python24.dll is compiled with /MD option. I was testing
it under debug version and that is compiled with /MDd option.
When i change the compiler option /MDd to /MD in my apps
debug version then the function works outside too.
Thanks
----------------------------------------------------------------------
Comment By: Vambola Kotkas (kotk)
Date: 2005-11-09 01:32
Message:
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Yes, first i did use that function in my application but it
surprizingly did not help. Googling about python IO
redirection indicated that some others have had similar
difficulties. So i debugged around and noticed that the very
table that my above function was meant to fix (possibly right
that it was named __pioinfo ... MS maps windows handles to
CRT FILE pointers there) had various locations. Maybe it was
because compiler /M option differed between the module
where i did IO redirection and with what python24.dll was
compiled. Like... say msvcr71d.dll was loaded for it but
msvcr71.dll loaded for python24.dll? :-/ I check it over again
when i get time.
Thanks.
----------------------------------------------------------------------
Comment By: Vambola Kotkas (kotk)
Date: 2005-11-09 01:32
Message:
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Thank you.
I've moved this feature request to PEP 42, "Feature Requests".
----------------------------------------------------------------------
Comment By: Martin v. Löwis (loewis)
Date: 2005-11-08 00:36
Message:
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I don't understand the remark "has its own rtl ioinfo
table". ioinfo is a type - what table are you referring to?
If you are talking about __pioinfo: this certainly isn't
defined per DLL. Instead, each copy of the MS C runtime has
one copy. Python (in 2.4) uses msvcr71.dll. So as long as
you also link against msvcr71.dll, you can modify the CRT
that Python uses without modifying python24.dll.
IOW, you can use your function in your application, and be done.
----------------------------------------------------------------------
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