MATLAB Compiler

C Shared Library

The MATLAB Compiler allows you to build a shared library from the files created in the previous section, "C Libraries." To build the shared library, libtimefun.ext, in one step, use

• mcc -B csharedlib:libtimefun weekday data tic calendar toc
  

This example uses the csharedlib bundle file

• -t -W lib:filename -T link:lib -h libmmfile.mlib
  

The bundle file option, -B <filename>:[<a1>,<a2>,...,<an>], replaces the entire expression on the mcc command line with the contents of the specified file and it allows you to use replacement parameters. This example uses the csharedlib bundle file and replaces the expression

• -B csharedlib:libtimefun
  

with

• -t -W lib:libtimefun -T link:lib -h libmmfile.mlib
  

giving the new statement

• mcc -t -W lib:libtimefun -T link:lib -h libmmfile.mlib weekday data tic calendar toc
  

The -t option tells the Compiler to generate C code from each of the listed M-files. The -T link:lib option tells the Compiler to compile and link a shared library. The -h option tells the Compiler to include any other M-functions called from those listed on the mcc command line, i.e., helper functions.

Note    You can use the -B option with a replacement expression as is at the DOS or UNIX prompt. To use -B with a replacement expression at the MATLAB prompt, you must enclose the expression that follows the -B in single quotes when there is more than one parameter passed. For example,     >>mcc -B csharedlib:libtimefun weekday data tic calendar toc can be used as is at the MATLAB prompt because libtimefun is the only parameter being passed. If the example had two or more parameters, then the quotes would be necessary as in     >>mcc -B 'cexcel:component,class,1.0' weekday data tic calendar toc

mlib Files

Shared libraries, like libraries, let you compile a common set of functions once and then compile other M-functions that depend on them without compiling them again.You accomplish this using mlib files, which are automatically generated when you generate the shared library.

Creating an mlib File.   When you create a library wrapper file, you also get a .mlib file with the same base name. For example,

•  mcc -W lib:libtimefun -L C -t -T link:lib -h weekday date tic calendar toc
  

creates

• libtimefun.c
  libtimefun.h
  libtimefun.exports
  libtimefun.mlib
  libtimefun.ext
  

The last file, libtimefun.ext, is the shared library file for your platform. For example, on the PC, the shared library is

• libtimefun.dll
  

Using an mlib File.   This example uses two functions, tic and toc, that are in the shared library. Consider a new function, timer, defined as

• function timer
      tic
          x = fft(1:1000);
      toc
  

Prior to mlib files, if you compiled timer using

• mcc -m timer
  

both tic and toc would be recompiled due to the implicit -h option included in the -m macro. Using mlib files, you would use

• mcc -m timer libtimefun.mlib
  

At compile time, function definitions for tic and toc are located in the libtimefun.mlib file, indicating that all future references to tic and toc should come from the mlib files's corresponding shared library. When the executable is created, it is linked against the shared library. For example, on the PC, the executable timer.exe is created and it is linked against libtimefun.dll.

An advantage of using mlib files is that the generated code is smaller because some of the code is now located in the shared library.

Note    On the mcc command line, you can access any mlib file by including the full path to the file. For example:     mcc -m timer /pathname/libtimefun.mlib

Restrictions.   

• (UNIX) The first three characters of the filename must be lib.
• (PC and UNIX) You cannot rename the file.
• (PC and UNIX) Both the shared library and the mlib file must be in the same directory at compile time.
• (PC and UNIX) At run time, the path to the shared library must be on the system's search path. For more information about setting the path on the PC, see Shared Libraries. For UNIX information, see Locating Shared Libraries. You do not need the mlib file present when running the executable that links to the shared library.

C Libraries

C++ Libraries