Do possible to generate c++ header file from dll export?

No, you can not (unless you disassemble to see how many variable ar passed and so on).

You can get name of Export Functions by using TDUMP.EXE (From Borland) or DUMPBIN.EXE (From Microsoft), but you can not find the arguments & return values in this manner.

If the DLL uses from _stdcall calling convention, you can see the disassemly of functions. Then try to find the return point of the function, at this location (return point) you will see ret n instruction. n/4 is the number of arguments passed to the function.
But if the DLL uses _cdecl calling convention, you should disassemble the application that calls these export functions. In this case, the no of pushes before function call or n/4 in the add esp,n after function call is the number of arguments.

[ArC]

Additionally you have to know the types of the arguments.
Sometimes functions expect pointers to complex strucutures. In that case only disassembling will help.

[bgrimm]

You could also try DLL2LIB, converts a DLL to a library file for static linking.

hxxp://www.binary-soft.com

Also available on the Ftp Site.

-bg

You can read this
How To Create 32-bit Import Libraries Without .OBJs or Source
hxxp://support.microsoft.com/kb/q131313/
and this
hxxp://www.codeproject.com/cpp/libfromdll.asp
I have used these methods to create a plugin for a program and used some dll from it.