MATLAB: Do I receive an error that “library name and function name are needed” when using the generic DLL interface in MATLAB 7.0 (R14) and later

callliberrorgenericlibraryloadlibraryMATLABr14r14sp1

When using LOADLIBRARY in MATLAB 7.0 (R14) and later, I receive the following error message:

 ??? Error using ==> calllib 
 To call a function both the library name and function name are needed.

Best Answer

This bug has been fixed in Release 14 Service Pack 3 (R14SP3). For previous product releases, read below for any possible workarounds:

A patch is available for MATLAB 6.5 (R13) to provide the interface to generic libraries. However, applying this patch to MATLAB 7.0 (R14) and later results in an error. The generic shared library functionality is now built in to the product. To remedy this error, reinstall MATLAB to use the most recent version of the generic library interface.

Related Solutions

MATLAB: Do I receive errors when trying to compile LOADLIBRARY or run an application that uses LOADLIBRARY with MATLAB Compiler 4.0 (R14)

This change has been incorporated into the documentation in Release 2011a (R2011a). For previous releases, read below for any additional information:

With MATLAB Compiler 4.0 (R14) and later, you can use MATLAB file prototypes as described below to load your library in a compiled application. Note that loading libraries using H-file headers is not supported in compiled applications.

This behavior occurs when LOADLIBRARY is compiled with the header argument as in the statement below:

loadlibrary(library, header)

In order to workaround this issue, execute the following command at the MATLAB commmand prompt:

loadlibrary(library, header, 'mfilename', 'mHeader');

... where mHeader is the name of a MATLAB file (in this case mHeader.m) that you would like to use when loading this library. This step only needs to be performed once to generate an MATLAB file for the library.

Now, in the code that is be compiled, you can call LOADLIBRARY with the following format:

loadlibrary(library, @mHeader, 'alias', alias)

With MATLAB Compiler versions 4.0.1 (R14+) and above, the generated MATLAB file mHeader.m will automatically be included in the CTF file as part of the compilation process. For versions 4.0 of the Compiler (R14) and later, include your library MATLAB file in the compilation with the '-a' option with MCC.

Note: With the MATLAB Compiler 3.0 (R13SP1) and earlier versions you cannot compile calls to LOADLIBRARY because of general restrictions and limitations of the MATLAB Compiler.

If you do not have a header file, the prototype file can be created manually. Follow the example in the documentation to generate a prototype file and modify it to suit the shared library you would like to use:

web([docroot,'/techdoc/ref/loadlibrary.html'])

MATLAB: Do I receive the warning “library class already exists” using LOADLIBRARY in MATLAB 7.0 (R14)

This warning occurs in MATLAB 7.0 (R14) and later due to the fact that the library class has already been loaded.

To prevent this warning, use the UNLOADLIBRARY command:

unloadlibrary libmx
hfile = [matlabroot '\extern\include\matrix.h'];
loadlibrary('libmx.dll', hfile)

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Related Solutions

MATLAB: Do I receive errors when trying to compile LOADLIBRARY or run an application that uses LOADLIBRARY with MATLAB Compiler 4.0 (R14)

MATLAB: Do I receive the warning “library class already exists” using LOADLIBRARY in MATLAB 7.0 (R14)

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