Hi,
rev 1.101 of winbase.h from 2010.08.24 introduces an anonymous structure
and union to the OVERLAPPED definition [1].
Unfortunately, this only works when compiling with -std=gnu99 (default),
but not with -std=c99.
The following demonstrates the problem:
----------------------------------------------------------------------
$ cat > overlapped_test.c << _EOL
#include <stdio.h>
#include <windows.h> /* includes winbase.h */
int main(int argc, char** argv) {
OVERLAPPED ov;
printf("size of OVERLAPPED: %d\n", sizeof(ov));
return 0;
}
_EOL
$ gcc -std=gnu99 -o overlapped_test overlapped_test.c
$ ./overlapped_test.exe
size of OVERLAPPED: 20
$ gcc -std=c99 -o overlapped_test overlapped_test.c
$ ./overlapped_test.exe
size of OVERLAPPED: 12
----------------------------------------------------------------------
The main issue appears to be that, since C99 does not support GNU99
anonymous structs/unions, it simply ignores them. But this wreaks havoc
on any source compiled in c99 mode that exchanges an OVERLAPPED with the
OS. This usually results in an "invalid handle error" from Windows.
Any application compiled in C99 mode and using OVERLAPPED is therefore
expected to break, and we have seen that issue after people upgraded
their cygwin installation and tried recompiling libusb [2]. Our current
workaround is to switch to gnu99, but with a source that is common to
both MSVC, MinGW and cygwin, GNU extensions is something we would like
to avoid. Also, the problem seems to have now spread to the latest
MinGW32 now (are they reusing cygwin's winbase.h?).
We would appreciate if you could look into this and ensure that
winbase.h is C99 compliant.
Regards,
/Pete
[1]
http://cygwin.com/cgi-bin/cvsweb.cgi/src/winsup/w32api/include/winbase.h.diff?r1=1.100&r2=1.101&cvsroot=src&f=h
[2]
http://git.libusb.org/?p=libusb-pbatard.git;a=commit;h=fb33bf26916dae3a443c9d831d5f9985f58bcc6b;js=1
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