Embedded MATLAB™

Setting C-MEX Compilation Options

About the C-MEX Compiler Configuration Object

Embedded MATLAB MEX provides a configuration object emlcoder.CompilerOptions for fine-tuning C-MEX compilation.

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Working with the C-MEX Compiler Configuration Object

To set C-MEX compilation options, follow these steps:

1. Define the compiler configuration object in the MATLAB workspace by issuing a constructor command, like this:

   comp_cfg = emlcoder.CompilerOptions

2. Modify the compilation options as necessary, either at the command line or using a dialog box.

3. Invoke emlmex with the -s option and specify the configuration object as its argument, as in this example:

   emlmex -s comp_cfg myMfile

   The -s option instructs emlmex to convert myFile.m to a C-MEX function, based on the compilation settings in comp_cfg.

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Modifying Compilation Options

There are two ways to modify compilation options for emlmex:

• Modifying Compilation Options at the Command Line Using Dot Notation

• Modifying Compilation Options Using a Dialog Box

Modifying Compilation Options at the Command Line Using Dot Notation

You can use dot notation to modify the value of one compilation option at a time, using this syntax:

configuration_object.property = value

Dot notation uses assignment statements to modify configuration object properties. For example, to change the maximum size function to inline and the stack size limit for inlined functions during C-MEX generation, enter this code at the command line:

co_cfg = emlcoder.CompilerOptions
co_cfg.InlineThreshold = 25;
co_cfg.InlineStackLimit = 4096;
emlmex -s co_cfg myFun

Modifying Compilation Options Using a Dialog Box

Besides using commands, you can modify compilation options using dialog boxes, as described in Compiler Options Dialog Box.

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How emlmex Resolves Conflicting Options

emlmex resolves options from left to right, so if you use conflicting options, the rightmost one prevails. For example, assume you define a compilation configuration object as follows:

co_cfg = emlcoder.CompilerOptions
co_cfg.InlineThreshold = 20;
co_cfg.InlineThresholdMax = 100;
co_cfg.InlineStackLimit = 5000;

What happens when you execute the following command?

emlmex -s co_cfg -O disable:inline myFun

None of your inlining options take effect because the -O option overrides the -s option to disable inlining.

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Making M-Code Compliant with the Embedded MATLAB Subset

Specifying Properties of Primary Function Inputs