Swapan Das
11th December 2007 06:57 UTC

Detect Windows Installer 3.1 using NSIS
Dear All,

Through my NSIS installer I want to detect whether WindowsInstaller 3.1 already exists in the system or not.

Hope, someone must have done this checking prior to the installation of WindowsInstaller 3.1

Regards,

Swapan Das
11th December 2007 08:38 UTC

In this meantime, I've worked around with the GetDLLVersion function and its giving me the version for it.
StrCpy $0 "$R2.$R3.$R4.$R5"
;$0 now contains the version string like "3.1.4000.2435"

So far its fine. Now how to compare the versions? The user may have Windows 3.0, then how to compare?

I tried with the following:
StrCpy $0 $0 "" 1
${VersionCompare} $0 "3.1" $1
${If} $1 == 2
MessageBox MB_YESNO "Windows Installer 3.1 or newer is required. You have $0. Upgrade WindowsInstaller?" IDYES InstallMSI
${Endif}

But the values are coming wrong for me:
$0 = .1.4000.2435 (instead of 3.1.4000.2435)
$1 = 2 (instead of 1)

kichik
11th December 2007 09:33 UTC

$0 is corrupted because you've corrupted it with the stray StrCpy command. It copies $0 into $0, skipping the first character.

Swapan Das
11th December 2007 13:06 UTC

Thanks kichik for going through my issue.

I've tried by removing the StrCpy command, still the version comparasion is not working on the desired way.
After removing the StrCpy command the value of:
$0 = 3.1.4000.2435
is coming fine, but now how to compare the mine's version with the user's version. If the $0 comes blank then I know WindowsInstaller is not installed and I can carry on with my installation but problem lies if the user is having lesser version then mine's 3.1 rather 3.1.4000.2435.

Regards,

kichik
12th December 2007 17:44 UTC

VersionCompare works fine for me, giving 1 in your case. What's the exact case where it fails for you?

Swapan Das
13th December 2007 04:40 UTC

Thanks for following the issue. Will get back to you soon with actual scenario. Was in a hurry, so packed the installer without version compare.

Regards,

lushdog
14th December 2007 14:05 UTC

You shouldn't have been able to compile it if you didn't include VersionCompare.

Swapan Das
15th December 2007 06:26 UTC

Originally posted by kichik
VersionCompare works fine for me, giving 1 in your case. What's the exact case where it fails for you?

kichik
15th December 2007 10:42 UTC

To check just replace $0 with whatever mock value you want.