Dear Friends, I am writing to call the APIs (functions) in the C DLL using perl CPAN Module Win32::API. The code works fine in the case where API expects input variable as Long. When the API expects the input as char *, i am not getting expected results. In the below, API, (1) and (2) are working fine. But API (3) has input parametes as char *. The result is signed long. In the working case, the result should return value greater than zero. but i am getting result as zero. Could you please advice me, how to pass the value as char * (C datatype) to the API as expected by API. Thanks in advance. Regards, Rags

DLL : mydll.dll

1) API Syntax: long CurrentDate(); 
use Win32::API;
my $dec = Win32::API->new('mydll.dll', 'CurrentDate', '', 'L') or die 
+$^E;
my $rv_bstr = $dec->Call();
($sec,$min,$hour,$day,$month,$year) = localtime($rv_bstr);
# correct the date and month for humans
$year = 1900 + $year;
$month++;
printf "%02d/%02d/%02d %02d:%02d:%02d\n", $year, $month,$day, $hour, $
+min, $sec;

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2) API Syntax: long GetVersion(char *pstrBuf, long lBuf); 
use Win32::API;
my $dec = Win32::API->new('mydll.dll', 'GetVersion', 'PN', 'L') or die
+ $^E;
my $lpBuffer = " " x 64;
$return = $dec->Call($lpBuffer, 64);
print $lpBuffer;

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3) API Syntax: long OpenConnection(char *strDataSource, char *strUser, char *strPwd); 
use Win32::API;
my $dec = Win32::API->new('mydll.dll', 'OpenConnection', 'PPP', 'L') o
+r die $^E;
$strDatabase = "test";
$strLoginUser = "test";
$strLoginPwd = "test";
# converting to C String
$db = pack('a*x', $strDatabase);
$user = pack('a*x', $strLoginUser);
$pwd = pack('a*x', $strLoginPwd); 

$return = $dec->Call($db, $user, $pwd);
print $return;

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In reply to Call C DLL Functions in Perl by sraghu_rs

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