VFP stores in an EXE/DLL information about what runtime DLL is required to run it.

? VfpVersionFromExeOrDll("C:\Program Files\My Company\MyVfpApplication.exe")
? VfpVersionFromExeOrDll("X:\Somefolder\MyVfpDll.dll")

Most Windows Shell and common controls DLLs implement DllGetVersion function. It allows applications to obtain DLL-specific version information to make sure that required functionality in a DLL is implemented.
The Windows API support class is used to handle Windows API structures.

$SAMPLECODE$


#DEFINE DLLVER_PLATFORM_WINDOWS 1
#DEFINE DLLVER_PLATFORM_NT 2

Adler32 is different from CRC32. It's much faster but a little bit less reliable.
The free ZLIB.DLL from http://www.zlib.net/ has a function to calculate Adler32.

$SAMPLECODE$

DECLARE Long adler32 IN Zlib Long Adler32, String Buffer, Long BuffLen

* Initialize Adler32 and calculate 1st checksum
lnAdler32 = adler32(0, Null, 0)
lcText = "Adler32 checksum"
lnAdler32 = adler32(lnAdler32, lcText, LEN(lcText))
? TRANSFORM(lnAdler32, "@0")