Perl Win32::API() call() function

Dear all, I am trying to get the value of char pointer or string in the return of call() function for my dll. my dll is having a function Rando开发者_StackOverflow社区mDec(long , int*) and returns a string. so what will be my call using Win32::API(). I have tried this and didn't succeed. plz help

use Win32::API;  
my @lpBuffer = " " x 20;   
my $pp= \@lpBuffer;  
my $xy=0;  
my $ff= \$xy;  
my $fun2 = new Win32::API('my.dll','RandomDec','NP','**P**')or die $^E;  
$pp = $fun2->Call(4,$ff);  

how to get using $pp ?

---

There are multiple errors in your code.

1. my @lpBuffer = " " x 20; my $pp= \@lpBuffer;

=> my $pp = " " x 20;

You are mixing arrays with strings, and you don't need a perl ref for a c ptr. Similar for the int*.

1. N is for number not long. L would be unsigned, you need signed, so l.

    use Win32::API;
    my $pp = " " x 20;   # alloc a string
    my $xy = 0;          # alloc an int
    my $fun2 = new Win32::API('my.dll','RandomDec','lP','P') or die $^E;  
    $pp = $fun2->Call(4,$xy);

I haven't check if Win32::API can do lvalue assignment to char*. Normally not, so $pp will be a foreign pointer to some string after the call, and the prev. PV slot for $pp will be lost, and inaccessible from perl. With FFI's and the WinAPI also you usually return int, not strings. Strings only via sideeffects, as function arg.