Re: Win32::API

[dada]

in reply to Win32::API

Guilderstern wrote:

There are two drawbacks to Win32::API that I've noticed so far. One could be easily remedied, while the other is probably not something I should hold my breath for...

hold your breath instead :-)
I'm working on a new release of Win32::API which will make your life a lot easier by supporting not only named types (eg. WORD, DWORD et al.) but structures too.

soon (I hope) you'll be able to say:

use Win32::API 0.40;

Win32::API::Struct->typedef 'POINT', qw(
    LONG x
    LONG y
);

Win32::API->Import(
    'user32',
    'BOOL GetCursorPos(LPPOINT lpPoint)'
);

my $point = Win32::API::Struct->new('POINT');
my $retval = GetCursorPos($point);

print "Cursor is at $point->{x}, $point->{y}\n";

...and callbacks will be there. I'm still cleaning things up, but I bet you'll be surprised :-)

oh, and BTW:

One example I'm thinking of is placing icons in the system tray. To be able to respond to mouse clicks, the function call that places the icon there must specify a callback that gets executed on a mouse click. AFAIK, there is no way to do this yet in Perl, and it may be impossible at the present.

well, there's Win32::GUI for this.

cheers,
Aldo

__END__
$_=q,just perl,,s, , another ,,s,$, hacker,,print;

[dada]

as promised (and after a mere 6 months or so :-), I've released version 0.40 of Win32::API.

it may not be on CPAN at the time I write, but here's the link to download it from my site:
Win32-API-0.40.tar.gz

the synopsis I gave in my previous message still applies :-)

there is even support for callbacks, but it is very experimental: feedback is appreciated as always.

cheers,
Aldo

King of Laziness, Wizard of Impatience, Lord of Hubris

[SyN/AcK]

Wow man, you must not really be the King of Laziness, cause this is awesome! I really appreciate your work.

[neauva]

Very nice and Very handy package.
I'm having a problem, however... :-)

In short, I'm trying to use Win32::API to call CreateProcess.

All is well except for the LPSTARTUPINFO and LPPROCESS_INFORMATION parms I pass into the call. If I create these using pack(...) for the correct number of bytes, it works fine and I can get the PID back out of the PROCESS_INFORMATION object (my ultimate goal).

If, however, I create these parms using the Win32::API::Struct->new( 'STARTUPINFO' ) approach, the call fails. I'm even setting the .cb field to the size of the structure. The error I get back (using Win32::GetLastError()) is "Invalid access to memory location". Here's the function call I'm making (same in both cases):



<-----------snip------------>

# version 1 - succeeds
my $si = pack( "L17", ((0) x 17) );
$si = pack( "LL16", length( $si ), ((0) x 16 ) );
my $pi = pack( "L4", ((0) x 4 ) );

# version 2 - fails
my $si = Win32::API::Struct->new( "STARTUPINFO" );
$si->{cb} = $si->sizeof();
my $pi = Win32::API::Struct->new( "PROCESS_INFORMATION" );

my $retval =
CreateProcess( "c:\\winnt\\notepad.exe",
               0,    # unused - cmdline ptr, unused
               0,    # unused - proc attributes ptr
               0,    # unused - thread attributes ptr
               0,    # unused - inherit handles
               0,    # unused - creation flags
               0,    # unused - env pointer
               0,    # unused - current dir ptr
               $si,
               $pi
             );

<-----------snip------------>

Should CreateProcess be called the same way in both cases? When a ->new('STARTUPINFO') is called, is the memory zeroed-out upon creation? Any idea why the pack version succeeds and the Struct verion fails?

TIA!
D. Smith

[BrowserUk]

At least part of the problem is that Win32::API::Struct (or rather, Win32::API::Type) does have support for the STARTUPINFO structure, or at least not as of version 0.41 which is the latest version I can find.

The fact that you aren't receiving the warnings I get:

Unknown Win32::API::Struct 'STARTUPINFO' at - line 7
Can't call method "sizeof" on an undefined value at - line 8, <DATA> l
+ine 164.

means that either

• you don't have warnings enabled.

  If so, turn them on, it'll save you much grief:)

• You have a later version of the package than I have been able to find.

  If so, which version is it and where can I get a copy:)

• You have a (locally?) modified copy of the package.

  If so, consult the people that made the modifications.

---

Examine what is said, not who speaks.
"Efficiency is intelligent laziness." -David Dunham
"When I'm working on a problem, I never think about beauty. I think only how to solve the problem. But when I have finished, if the solution is not beautiful, I know it is wrong." -Richard Buckminster Fuller
If I understand your problem, I can solve it! Of course, the same can be said for you.