Can I rely on OSVERSIONINFO.szCSDVersion or Environment.OSVersion.ServicePack to always be of the form “Service Pack X”?

Question

The title basically says it all. I need to determine the Windows Service Pack number (in numeric form), and Environment.OSVersion.ServicePack (which basically just returns OSVERSIONINFO.szCSDVersion) just returns a string.

In all my tests, this string turned out to be in the form "" (no service pack) or "Service Pack X", with X being a number. So the algorithm to parse this should be quite simple.

My question: Can I rely on this string to always have this format?

(One part of me says no, beause it's not documented. The other part says yes, because surely a lot of existing code would break if MS would decide to return, say, "SP 2 (x86)" for Windows 7 SP2. Thus, they won't do it. Does anyone have more information on that?)

Answer 1

No you can't, some versions use translated strings! If you look at the strings from the image in that link you see that you might get away with just using the first number you find in the string.

OSVERSIONINFOEX was added in NT4 SP6, if you call GetVersionEx you only need to deal with the string on Win9x and < NT4 SP6 and use OSVERSIONINFOEX.wServicePackMajor on other systems.

Answer 2

You should use BuildLabEx instead. It has a specified format which has held since early builds of Windows. Not sure if you can find it in WMI (you should be able to), but it's in the registry:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\BuildLabEx

Example:

7601.17640.amd64fre.win7sp1_gdr.110632-1508

If it makes you feel more comfortable, you could rely initially on CSDVersion matching a certain regex for simplicity, and fail back onto BuildLabEx if it doesn't match.