JNI Tutorial (Step 5)

[Michael Brewer]

I'm going through the JNI Tutorial on Sun's Website. I'm on step 5 and I can't seem to get the C file compiled into a DLL. I understand that this isn't really a Java question, but I'm not a C guy, I have nowhere else to go, and I encountered this problem in the midst of a Java tutorial, so...
Can someone tell me how to compile the C file into a DLL? I'm entering the following on the command line:

cl -IC:\Java\j2sdk1.4.1_01\include -IC:\Java\j2sdk1.4.1_01\include\win32 -LD HelloWorldImp.c -Fehello.dll

And I get the following error:

Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 13.00.9466 for 80x86
Copyright (C) Microsoft Corporation 1984-2001. All rights reserved.
HelloWorldImp.c
C:\Java\j2sdk1.4.1_01\include\jni.h(21) : fatal error C1083: Cannot open include
 file: 'stdio.h': No such file or directory

I copied stdio.h into the same folder as my Java, header, and C files. But, it still gives me this error. Can anyone help?

[Vikas Varma]

I think it requires the standard stdio.h files for the VC++ compiler. Usually it should be there ur msvc++ directory.
Try using the -I flag and initialize it to the VC++ include files. For example -I c:\msvc++\include.
Hope it works..
--Vikas

[Michael Brewer]

OK, I changed my command string to:

cl -IC:\Java\j2sdk1.4.1_01\include -IC:\Java\j2sdk1.4.1_01\include\win32 -I"C:\Program Files\Microsoft\Visual Studio .NET\Vc7\include" -LD HelloWorldImp.c -Fehello.dll

And now I get the following error:

Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 13.00.9466 for 80x86
Copyright (C) Microsoft Corporation 1984-2001. All rights reserved.
HelloWorldImp.c
Microsoft (R) Incremental Linker Version 7.00.9466
Copyright (C) Microsoft Corporation.  All rights reserved.
/dll
/implib:hello.lib
/out:hello.dll
HelloWorldImp.obj
LINK : fatal error LNK1104: cannot open file 'LIBCMT.lib'

And now I'm completely baffled. I would really appreciate any help on this.

[Michael Brewer]

Originally posted by Vikas Varma:
Try using the -I flag and initialize it to the VC++ include files. For example -I c:\msvc++\include.

Thanks. I didn't see your post until after I posted my second comment. Is JavaRanch slow on updating threads or did my browser just not reload the page?

[Vikas Varma]

Originally posted by Michael Brewer:

Thanks. I didn't see your post until after I posted my second comment. Is JavaRanch slow on updating threads or did my browser just not reload the page?

Ok! now I think the C program has compiled successfully.
Now its a Linking error.
Check out the options for setting the library path for linking the libraries.
--Vikas

[Michael Brewer]

Thanks Vikas.
Thanks to this page I found out that I needed to run

vcvars32

in order to setup the environment. Why I should have to do that on Windows, I don't know. I then got the following response which I assume is successful:

Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 13.00.9466 for 80x86
Copyright (C) Microsoft Corporation 1984-2001. All rights reserved.
HelloWorldImp.c
Microsoft (R) Incremental Linker Version 7.00.9466
Copyright (C) Microsoft Corporation.  All rights reserved.
/dll
/implib:hello.lib
/out:hello.dll
HelloWorldImp.obj
   Creating library hello.lib and object hello.exp

On to step 6!
[ February 13, 2003: Message edited by: Michael Brewer ]