RhetTbull
stranger
Nov 18, 2001, 10:43 AM
Post #5 of 8
(1309 views)
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Yes, you can. You don't need to import the header files if the API lives in a DLL and you know the prototype declaration. You need the Win32::API module (you can install this via ActiveState's ppm). Here's an example of using Win32::API to import and use an API routine (GetShortPathName which gets the MSDOS'ified version of a Windows file name)
#---start of script---
use strict;
use warnings;
use Win32::API;
#import the function
#GetShortPathName is in kernel32.dll, it takes two pointers to strings and a DWORD and returns a DWORD
my $GetShortPathName = new Win32::API("kernel32","GetShortPathName",[ qw(P P N) ],'N');
die "could not import GetShortPathName" if not defined $GetShortPathName;
#the name we want to convert
my $longname = 'C:\Program Files\Microsoft Office\Office\OFREAD9.TXT';
#create a string big enough to hold the shortname
my $shortname = " " x 80;
#retval will be length of the DOSified short name
my $retval = $GetShortPathName->Call($longname,$shortname,80);
print "retval = $retval\n";
#trim the trailing blanks
#recall that $shortname = " " x 80
#and retval is the length of the name returned by GetShortPathName
$shortname = substr($shortname,0,$retval);
print "longname = \n\"$longname\", \nshortname = \n\"$shortname\"";
#---end of script---
On my system, this outputs:
retval = 39
longname =
"C:\Program Files\Microsoft Office\Office\OFREAD9.TXT",
shortname =
"C:\PROGRA~1\MICROS~2\Office\OFREAD9.TXT"
One more example, using SystemParametersInfo to change the wallpaper:
#---start of script---
use strict;
use warnings;
use Win32::API;
my $SystemParametersInfo = new Win32::API("user32","SystemParametersInfo",[ qw(I I P I) ],'I');
if (not defined $SystemParametersInfo ) {
die "could not import SystemParametersInfo";
}
my $wallpaper = "c:\\winnt\\Blue Lace 16.bmp";
my $action = 20; #reference http://support.microsoft.com/support/kb/articles/Q97/1/42.ASP to see which constant to use
my $saveWinINI = 0; #save this in the user profile?
my $param = 0; #dependent on what $action is
#change the wallpaper
my $retval = $SystemParametersInfo->Call($action,$param,$wallpaper,$saveWinINI);
print "SystemParametersInfo returned $retval\n";
#---end of script---
Good luck! This method works great for importing predefined APIs that live in DLLs. If you need more complex interfacing then look into XS or Swig.
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