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[netCDF #QTJ-204110]: Using NetCDF libraries with the LCC compiler in

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  • Subject: [netCDF #QTJ-204110]: Using NetCDF libraries with the LCC compiler in
  • Date: Fri, 13 Jun 2008 06:59:06 -0600
> To whom it may concern:
>
>
>
> I have written a host of NetCDF functions in C that I use
> on Linux with gcc.  I have tried to port the source code to Windows and
> am trying to compile with LCC in MATLAB.  I have read the documentation
> provided for using NetCDF in Windows (set the preprocessor flag
> DLL_NETCDF, and place the ncgen.exe, ncdump.exe, netcdf.dll and .lib
> file in WINDOWS\system32\), but I am getting errors in the netcdf.h file
> when compiling; the compiler does not understand the function
> __declspec(dllimport).  Is this supposed to be included from the
> netcdf.dll library?  Do I need to compile the netcdf.dll from scratch
> and not use the prebuilt one for Windows?  Any help would be
> appreciated.  Here is the compiler command I am using and output.
>
>
>
> "lcc  -c -Zp8 -I"C:\Program Files\MATLAB704\sys\lcc\include"
> -DMATLAB_MEX_FILE -DDLL_NETCDF -noregistrylookup -Fogetncground.obj
> -I"C:\Program Files\MATLAB704"\extern\include -I"C:\Program
> Files\MATLAB704"\simulink\include -DNDEBUG getncground.c"
>

Howdy Jeremy!

Unfortunately I don't have the LCC compiler, nor do I use MATLAB, nor do I know
how to compile C code into it. (I didn't even know you could do that!)

I believe MATLAB already can read netCDF files - is that correct? If so, you
should not have to install or build the netcdf library, because it is already
there and being used. I don't know if netcdf access come with MATLAB or whether
you have to somehow install it, but I would think the easiest way to proceed
would be to get netCDF working within MATLAB.

Once that is working, try compiling your code again.

To answer some of your specific questions:

The __declspec(dllimport) is a Microsoft thing that is required in
windows-based compilers to "import" the function from the DLL. How can MATLAB
provide a compiler on windows that doesn't use declspec? I don't know,
obviously. That surprises me. What you need to do is find out how LCC wants you
to tell it that nc_open (for example) is coming from a DLL. (I know, in gcc you
don't have to tell it, but in Windows you do.)

Once you figure out what LCC wants instead of __declspec, you can see how to
get the netcdf.h file to reflect that.

You should not have to compile netcdf from scratch - but how to get LCC to use
a DLL is not clear to me.

Surely there are others who have gotten their own C/netcdf code working withing
MATLAB on windows. I suggest you ask on the netcdf mailing list, and whatever
matlab mailing list seems appropriate.

Good luck,

Ed

Ticket Details
===================
Ticket ID: QTJ-204110
Department: Support netCDF
Priority: Normal
Status: Closed