coder.MexCodeConfig

Configuration parameters for MEX function generation from MATLAB code

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Description

A coder.MexCodeConfig object contains the configuration parameters that codegen uses when generating a MEX function. Pass the object to the codegen function by using the -config option.

Creation

Syntax

cfg = coder.config('mex')
cfg = coder.config

Description

example

cfg = coder.config('mex') creates a coder.MexCodeConfig object.

cfg = coder.config creates a coder.MexCodeConfig object.

Properties

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Maximum number of function specializations for compile-time recursion, specified as a positive integer. To disallow recursion in the MATLAB® code, set CompileTimeRecursionLimit to 0. The default compile-time recursion limit is large enough for most recursive functions that require this type of recursion. If code generation fails because of the compile-time recursion limit, and you want compile-time recursion, try to increase the limit. Alternatively, change your MATLAB code so that the code generator uses run-time recursion. See Compile-Time Recursion Limit Reached.

Maximum number of instructions that the constant folder executes. In some situations, code generation requires specific instructions to be constant. If constant folding stops before these instructions are constant-folded, code generation fails. In this case, increase the value of ConstantFoldingTimeout.

See MATLAB Coder Optimizations in Generated Code.

Constant input checking mode, specified as one of the values in this table.

ValueDescription
'CheckValues'

This value is the default value.

When you call the MEX function, it checks that the value you provide for a constant input argument is the value specified at code generation time.

You can call the MEX function and the original MATLAB function with the same arguments. Therefore, you can use the same test file for both functions.

Checking the values can slow down execution of the MEX function.

'IgnoreValues'

When you call the MEX function, it ignores the value that you provide for a constant input argument. It uses the value specified at code generation time.

You can use the same test file without the overhead of checking the constant argument values.

'Remove'

The code generator removes constant input arguments from the MEX function signature. When you call the MEX function, you do not provide a value for a constant input argument.

This option provides backward compatibility.

See Constant Input Checking in MEX Functions.

Whether to generate C++ namespaces for the packages in your MATLAB code, specified as one of the values in this table.

ValueDescription
true

This value is the default value.

The code generator produces C++ namespaces for the packages in your MATLAB code. See Organize Generated C++ Code into Namespaces.

false

The code generator does not produce C++ namespaces for the packages in your MATLAB code.

Dependency:

  • Setting TargetLang to 'C++' enables this parameter.

Data Types: logical

Namespace for the generated C++ code. The code generator does not produce code in a namespace unless you specify a nonempty character vector.

See Organize Generated C++ Code into Namespaces.

Dependency:

  • Setting TargetLang to 'C++' enables this parameter.

Namespace for the C++ code generated for MathWorks code. The code generator does not produce such a namespace if you specify this property as an empty character vector.

See Organize Generated C++ Code into Namespaces.

Dependency:

  • Setting TargetLang to 'C++' enables this parameter.

Data Types: char

Whether to generate C++ classes or C style structures for MATLAB classes, specified as one of the values in this table.

ValueDescription
true

This value is the default value.

The code generator produces C++ classes for MATLAB classes. See Generate C++ Classes for MATLAB Classes.

false

The code generator produces C style structures for MATLAB classes.

Dependency:

  • Setting TargetLang to 'C++' enables this parameter.

Data Types: logical

Custom code that appears near the top of each C/C++ header file generated from your MATLAB code, except rtwtypes.h and rtwhalf.h, specified as a character vector.

Include folders to add to the include path when compiling the generated code. Specify the list of include folders as a character vector. In the character vector, separate include folders by a pathsep character. For example:

cfg = coder.config('mex');
cfg.CustomInclude = ['C:\Project' pathsep 'C:\Custom Files'];

Custom code to include in the generated initialize function, specified as a character vector.

Static library files to link with the generated code, specified as a character vector. In the character vector, separate library file names by a pathsep character.

Source files to compile and link with the generated code, specified as a character vector. In the character vector, separate source file names by a pathsep character.

The build process searches for the source files first in the current folder, and then in the include folders that you specify in CustomInclude. If source files with the same name occur in multiple folders on the search path, the build process might use a different file than the file that you specified.

Suppose that you specify foo.cpp as a source file. If foo.c and foo.cpp are both on the search path, you cannot be sure whether the build process uses foo.c or foo.cpp.

Specify code to appear near the top of each generated .c or .cpp file (except rtwhalf.c or rtwhalf.cpp), outside of any function. Specify code as a character vector.

Do not specify a C static function definition.

Code that appears in the generated terminate function, specified as a character vector.

Configuration object for code generation for deep learning networks, specified as a coder.MklDNNConfig object.

A coder.MklDNNConfig object contains parameters specific to C++ code generation for deep learning using Intel® MKL-DNN. To create a coder.MklDNNConfig object, use coder.DeepLearningConfig. For example: 

cfg = coder.config('mex');
cfg.TargetLang = 'C++';
cfg.DeepLearningConfig = coder.DeepLearningConfig('mkldnn');

Code generation for deep learning networks requires Deep Learning Toolbox™ and the MATLAB Coder™ Interface for Deep Learning Libraries support package.

See Code Generation for Deep Learning Networks with MKL-DNN.

Note

MEX code generation is not supported for deep learning using the ARM® Compute Library.

Dependency: If DeepLearningConfig is set, codegen sets TargetLang to C++.

Dynamic memory allocation mode, specified as one of the values in this table.

ValueDescription
'Threshold'

This value is the default value.

The code generator allocates memory dynamically on the heap for variable-size arrays whose size (in bytes) is greater than or equal to DynamicMemoryAllocationThreshold.

'AllVariableSizeArrays'The code generator dynamically allocates memory for all variable-size arrays on the heap.
'Off'

The code generator statically allocates memory for variable-size arrays on the stack.

Unbounded variable-size arrays require dynamic memory allocation.

Dependencies:

  • EnableVariableSizing enables this parameter.

  • Setting this DynamicMemoryAllocation to 'Threshold' enables the DynamicMemoryAllocationThreshold parameter.

See Generate Code for Variable-Size Data.

Implementation of dynamically allocated array at the interface of the generated C/C++ function, specified as one of the values in this table.

ValueDescription
'Auto'

This is the default value. If you set the TargetLang parameter to 'C++' or 'C', this value correspondingly behaves as the same flag.

'C'

The generated code uses the C style emxArray data structure to implement dynamically allocated arrays. See Use C Arrays in the Generated Function Interfaces.

'C++'

If you set the TargetLang parameter to 'C', this value is disabled.

The generated code uses the coder::array class template to implement dynamically allocated arrays. See Use Dynamically Allocated C++ Arrays in the Generated Function Interfaces.

Dependency:

  • EnableVariableSizing enables this parameter.

Size threshold for dynamic memory allocation of variable-size arrays, specified as a positive integer. The code generator uses dynamic memory allocation for variable-size arrays whose size (in bytes) is greater than or equal to the threshold.

Dependency:

  • Setting DynamicMemoryAllocation to 'Threshold' enables this parameter.

See Generate Code for Variable-Size Data.

Expression echoing, specified as one of the values in this table.

ValueDescription
true

This value is the default value.

The MEX function displays the output of statements that do not end with a semicolon.

false

The MEX function does not display the output of statements that do not end with a semicolon.

This property does not apply to common visualization functions, such as disp, plot, or figure when they are called as an extrinsic function. MEX functions display the output of those functions regardless of the presence of a semicolon or the value of EchoExpressions.

Automatic extrinsic function calls, specified as one of the values in this table.

ValueDescription
true

This value is the default value.

The code generator treats some common visualization functions as extrinsic functions. You do not have to declare these functions as extrinsic by using coder.extrinsic. This capability reduces the amount of time that you spend making your code suitable for code generation.

falseThe code generator does not treat common visualization functions as extrinsic functions unless you declare them as extrinsic by using coder.extrinsic.

Some common visualization functions are plot, disp, and figure. See Extrinsic Functions.

C compiler debugging mode, specified as one of the values in this table.

ValueDescription
false

This value is the default value.

The code generator does not enable the C compiler debugging mode.

true

The code generator enables the C compiler debugging mode. When debugging mode is enabled, the C compiler does not optimize the code. The compilation is faster, but the execution is slower.

Just-in-time (JIT) compilation mode, specified as one of the values in this table.

ValueDescription
false

This value is the default value.

The code generator creates a C/C++ MEX function by generating and compiling C/C++ code.

true

The code generator uses just-in-time (JIT) compilation technology for MEX function generation. The code generator creates a JIT MEX function that contains an abstract representation of the MATLAB code. When you run the JIT MEX function, MATLAB generates the executable code in memory.

To speed up generation of MEX functions, set EnableJIT to true.

JIT compilation is incompatible with certain code generation features and options, such as custom code or use of the OpenMP library. If you specify JIT compilation and the code generator is unable to use it, it generates a C/C++ MEX function with a warning. If EnableJIT and EnableOpenMP are true, and your code uses parfor, the code generator uses JIT compilation and treats the parfor-loops as for-loops.

See Speed Up MEX Generation by Using JIT Compilation.

memcpy optimization, specified as one of the values in this table.

ValueDescription
true

This value is the default value.

If possible, the code generator uses the memcpy optimization. To optimize code that copies consecutive array elements, the memcpy optimization replaces the code with a memcpy call. When the number of elements to copy is known at compile time, the code generator uses the MemcpyThreshold property to determine whether to use the optimization. See memcpy Optimization.

false

The code generator does not use the memcpy optimization.

Enabling profiling of generated MEX function, specified as one of the values in this table.

ValueDescription
false

This value is the default value.

The code generator does not include the instrumentation for profiling in the generated MEX function.

true

The code generator includes the instrumentation for profiling in the generated MEX function. You can then use the MATLAB Profiler to profile the MEX. See Profile MEX Functions by Using MATLAB Profiler.

Parallelization of parfor-loops, specified as one of the values in this table.

ValueDescription
true

This value is the default value.

If possible, the code generator uses the OpenMP library to produce loop iterations that run in parallel.

false

The code generator treats parfor-loops as for-loops.

See parfor.

Use of the OpenMP library is not compatible with just-in-time (JIT) compilation. If EnableJIT and EnableOpenMP are true, the code generator uses JIT compilation and treats parfor-loops as for-loops.

Run-time recursion support, specified as one of the values in this table.

ValueDescription
true

This value is the default value.

Recursive functions are allowed in the generated code.

false

Recursive functions are not allowed in the generated code.

Some coding standards, such as MISRA®, do not allow recursion. To increase the likelihood of generating code that is compliant with MISRA C®, set EnableRuntimeRecursion to false.

If your MATLAB code requires run-time recursion and EnableRuntimeRecursion is false, code generation fails.

See Code Generation for Recursive Functions.

Variable-size array support, specified as one of the values in this table.

ValueDescription
true

This value is the default value.

Variable-size arrays are allowed for code generation.

false

Variable-size arrays are not allowed for code generation.

Dependency:

  • Enables Dynamic memory allocation.

See Code Generation for Variable-Size Arrays.

Extrinsic function call support, specified as one of the values in this table.

ValueDescription
true

This value is the default value.

For an extrinsic function, the code generator produces a call to a MATLAB function. The code generator does not generate the internal code for the function.

false

The code generator ignores an extrinsic function. It does not generate code for the call to the MATLAB function. If the extrinsic function affects the output of the MATLAB function, the code generator issues a compilation error.

If you set ExtrinsicCalls to false, the generated MEX function cannot display run-time messages from error or assert statements in your MATLAB code. The MEX function reports that it cannot display the error message. To see the error message, set ExtrinsicCalls to true and generate the MEX function again.

The value of ExtrinsicCalls affects how a MEX function generates random numbers for rand, randi, and randn. If ExtrinsicCalls is true, the MEX function uses the MATLAB global random number stream to generate random numbers. Otherwise, the MEX function uses a self-contained random number generator.

See Extrinsic Functions.

File partitioning mode specified as one of the values in this table.

ValueDescription
'MapMFileToCFile'

This value is the default value.

The code generator produces separate C/C++ files for each MATLAB language file.

'SingleFile'The code generator produces a single file for C/C++ functions that map to your MATLAB entry-point functions. The code generator produces separate C/C++ files for utility functions.

See How MATLAB Coder Partitions Generated Code.

Generation of only source code, specified as one of the values in this table.

ValueDescription
false

This value is the default value.

The code generator produces C/C++ source code and builds object code.

true

The code generator produces C/C++ source code, but does not invoke the make command or build object code. When you iterate between modifying MATLAB code and generating C/C++ code, generating only code can save time.

Comments in generated code, specified as one of the values in this table.

ValueDescription
true

This value is the default value.

The code generator places comments in the generated code.

falseThe code generator does not place comments in the generated code.

Code generation report, specified as one of the values in this table.

ValueDescription
false

This value is the default value.

The code generator produces a report only if error or warning messages occur, or if you set LaunchReport to true.

trueThe code generator produces a code generation report.

Global data synchronization mode, specified as one of the values in this table.

ValueDescription for Global DataDescription for Constant Global Data

'SyncAlways' (default)

This value is the default value.

Synchronizes global data at MEX function entry and exit and for extrinsic calls for maximum consistency between MATLAB and the generated MEX function. To maximize performance, if the extrinsic calls do not change global data, use this option with the coder.extrinsic -sync:off option to turn off synchronization for these calls.

Verifies consistency of constant global data at MEX function entry and after extrinsic calls. If the global data values in the MATLAB global workspace are inconsistent with the compile-time constant global values in the MEX function, the MEX function ends with an error. Use the coder.extrinsic -sync:off option to turn off consistency checks after specific extrinsic calls.

'SyncAtEntryAndExits'

Synchronizes global data at MEX function entry and exit only. To maximize performance, if only a few extrinsic calls change global data, use this option with the coder.extrinsic -sync:on option to turn on synchronization for these calls.

Verifies constant global data at MEX function entry only. If the global data values in the MATLAB global workspace are inconsistent with the compile-time constant global values in the MEX function, the MEX function ends with an error. Use the coder.extrinsic -sync:on option to turn on consistency checks after specific extrinsic calls.

'NoSync'

Disables synchronization. Before disabling synchronization, verify that your MEX function does not interact with MATLAB global data. Otherwise, inconsistencies between MATLAB and the MEX function can occur.

Disables consistency checks.

See Generate Code for Global Data.

Display of potential row-major layout efficiency issues, specified as one of the values in this table.

ValueDescription
true

The code generation report displays potential efficiency issues due to row-major layout. (This value is the default value.)

falseThe code generation report does not display issues related to array layout.

See Code Design for Row-Major Array Layout.

Assignment of float and double zero with memset, specified as one of the values in this table.

ValueDescription
true

This value is the default value.

If possible, the code generator uses the memset optimization for assignment of floating-point zero to consecutive array elements. To assign consecutive array elements, the memset optimization uses a memset call. When the number of elements to assign is known at compile time, the code generator uses the MemcpyThreshold property to determine whether to use the optimization. See memset Optimization.

false

The code generator does not use the memset optimization for assignment of float and double zero to consecutive array elements.

Inlining behavior at all call sites where a MathWorks calls another MathWorks function, specified as one of the values in this table.

ValueDescription
'Speed'

This value is the default value.

Uses internal heuristics to determine whether to perform inlining at a call site. This setting usually leads to highly optimized code.

'Always'

Always performs inlining at a call site.

'Readability'

Almost never inlines function calls, except for calls to very small functions. Preserves modularity of code without sacrificing too much speed, whenever possible. Results in highly readable code.

'Never'

Never inlines function calls. Results in maximum readability. This setting might significantly reduce the performance of the generated code.

Even if you select the 'Always' or the 'Never' option for a setting, in certain cases, the code generator might not strictly follow that instruction. For example, if there is a conflict, the coder.inline('always') or coder.inline('never') directive placed inside a function body overrides this option. For more information, see Interaction Between Different Inlining Controls.

See Control Inlining to Fine-Tune Performance and Readability of Generated Code.

Inlining behavior at all call sites where a function that you wrote calls a MathWorks function, or a MathWorks function calls a function that you wrote. Specified as one of the values in this table.

ValueDescription
'Speed'

This value is the default value.

Uses internal heuristics to determine whether to perform inlining at a call site. This setting usually leads to highly optimized code.

'Always'

Always performs inlining at a call site.

'Readability'

Almost never inlines function calls, except for calls to very small functions. Preserves modularity of code without sacrificing too much speed, whenever possible. Results in highly readable code.

'Never'

Never inlines function calls. Results in maximum readability. This setting might significantly reduce the performance of the generated code.

Even if you select the 'Always' or the 'Never' option for a setting, in certain cases, the code generator might not strictly follow that instruction. For example, if there is a conflict, the coder.inline('always') or coder.inline('never') directive placed inside a function body overrides this option. For more information, see Interaction Between Different Inlining Controls.

See Control Inlining to Fine-Tune Performance and Readability of Generated Code.

Inlining behavior at all call sites where a function that you wrote calls another function that you wrote, specified as one of the values in this table.

ValueDescription
'Speed'

This value is the default value.

Uses internal heuristics to determine whether to perform inlining at a call site. This setting usually leads to highly optimized code.

'Always'

Always performs inlining at a call site.

'Readability'

Almost never inlines function calls, except for calls to very small functions. Preserves modularity of code without sacrificing too much speed, whenever possible. Results in highly readable code.

'Never'

Never inlines function calls. Results in maximum readability. This setting might significantly reduce the performance of the generated code.

Even if you select the 'Always' or the 'Never' option for a setting, in certain cases, the code generator might not strictly follow that instruction. For example, if there is a conflict, the coder.inline('always') or coder.inline('never') directive placed inside a function body overrides this option. For more information, see Interaction Between Different Inlining Controls.

See Control Inlining to Fine-Tune Performance and Readability of Generated Code.

Memory integrity checking, specified as one of the values in this table.

ValueDescription
true

This value is the default value.

The generated code detects memory integrity violations and stops execution with a diagnostic message.

false

The generated code does not detect memory integrity violations.

Setting IntegrityChecks to false can improve performance. However, without memory integrity checks, violations result in unpredictable behavior. Set IntegrityChecks to false only if you have verified that array bounds checking and dimension checking are unnecessary. Setting IntegrityChecks to false also disables the run-time stack.

See Control Run-Time Checks.

Automatic open of code generation report, specified as one of the values in this table.

ValueDescription
false

This value is the default value.

If errors or warnings occur, or if GenerateReport is true, the code generator produces a report, but does not open the report.

trueThe code generator produces and opens a code generation report.

Inclusion of MATLAB source code as comments in generated code, specified as one of the values in this table.

ValueDescription
false

This value is the default value.

The code generator does not insert MATLAB source code as comments in the generated code. The code generator does not include the MATLAB function signature in the function banner.

true

The code generator inserts MATLAB source code as comments in the generated code. A traceability tag immediately precedes each line of source code. The traceability tag helps you to locate the corresponding MATLAB source code. See Tracing Generated C/C++ Code to MATLAB Source Code.

The code generator also includes the MATLAB function signature in the function banner.

Dependency:

  • GenerateComments enables this parameter.

See Tracing Generated C/C++ Code to MATLAB Source Code.

Minimum size, in bytes, for memcpy or memset optimization, specified as a positive integer.

To optimize generated code that copies consecutive array elements, the code generator tries to replace the code with a memcpy call. To optimize generated code that assigns a literal constant to consecutive array elements, the code generator tries to replace the code with a memset call.

The number of bytes is the number of array elements to copy or assign multiplied by the number of bytes required for the C/C++ data type.

If the number of elements to copy or assign is variable (not known at compile time), the code generator ignores the MemcpyThreshold property.

See memcpy Optimization and memset Optimization.

Object name, specified as a character vector.

Command to customize build processing after MEX function generation with codegen, specified as a character vector.

See Build Process Customization.

Generation of code that uses N-dimensional indexing, specified as one of the values in this table.

ValueDescription
false

Generate code that uses one-dimensional indexing. (This value is the default value.)

trueGenerate code that uses N-dimensional indexing.

See Generate Code That Uses N-Dimensional Indexing.

Variable names to preserve in the generated code, specified as one of the values in this table.

ValueDescription
'None'

This value is the default value.

The code generator does not have to preserve any variable names. It can reuse any variables that meet the requirements for variable reuse.

If your code uses large structures or arrays, setting PreserveVariableNames to 'None' can reduce memory usage or improve execution speed.

'UserNames'

The code generator preserves names that correspond to variables that you define in the MATLAB code. It does not replace your variable name with another name and does not use your name for another variable. To improve readability, set PreserveVariableNames to 'UserNames'. Then, you can more easily trace the variables in the generated code back to the variables in your MATLAB code.

Setting PreserveVariableNames to 'UserNames' does not prevent an optimization from removing your variables from the generated code or prevent the C/C++ compiler from reusing the variables in the generated binary code.

'All'

Preserve all variable names. This parameter value disables variable reuse. Use it only for testing or debugging, not for production code.

See Preserve Variable Names in Generated Code.

Name of variable to which you export information about code generation, specified as a character vector. The code generator creates this variable in the base MATLAB workspace. This variable contains information about code generation settings, input files, generated files, and code generation messages.

See Access Code Generation Report Information Programmatically and coder.ReportInfo Properties.

Potential difference reporting, specified as one of the values in this table:

ValueDescription
trueThe code generator reports potential behavior differences between generated code and MATLAB code. The potential differences are listed on a tab of the code generation report. A potential difference is a difference that occurs at run time only under certain conditions.
falseThe code generator does not report potential differences.

See Potential Differences Reporting.

List of names that code generator must not use for functions or variables, specified as a character vector or string scalar. To specify multiple reserved names, use a semicolon-separated list of reserved names in ReservedNameArray. For example, cfg.ReservedNameArray = "reserve1;reserve2;reserve3".

Responsiveness checks, specified as one of the values in this table.

ValueDescription
true

This value is the default value.

You can use Ctrl+C to stop execution of a generated MEX function.

false

To end a long-running MEX function, you might have to terminate MATLAB.

See Control Run-Time Checks.

Generation of code that uses row-major array layout, specified as one of the values in this table.

ValueDescription
false

Generate code that uses column-major array layout. (This value is the default value.)

trueGenerate code that uses row-major array layout.

See Generate Code That Uses Row-Major Array Layout.

Integer overflow support, specified as one of the values in this table.

ValueDescription
true

This value is the default value.

The code generator produces code to handle integer overflow. Overflows saturate to either the minimum or maximum value that the data type can represent.

false

The code generator does not produce code to handle integer overflow. Do not set SaturateOnIntegerOverflow to false unless you are sure that your code does not depend on integer overflow support. If you disable integer overflow support and integrity checks are enabled, the generated code produces an error for overflows. If you disable integer overflow support and you disable integrity checks, the overflow behavior depends on your target C compiler. In the C standard, the behavior for integer overflow is undefined. However, most C compilers wrap on overflow.

This parameter applies only to MATLAB built-in integer types. It does not apply to doubles, singles, or fixed-point data types.

See Disable Support for Integer Overflow or Nonfinites.

Maximum stack usage per application, in bytes, specified as a positive integer. Set a limit that is lower than the available stack size. Otherwise, a run-time stack overflow might occur. The C compiler detects and reports stack overflows.

See Control Stack Space Usage.

Language to use in generated code, specified as 'C' or 'C++'. If you specify C++, the code generator wraps the C code into .cpp files so that you can use a C++ compiler and interface with external C++ applications. It does not generate C++ classes.

Dependency: If DeepLearningConfig is set, codegen sets TargetLang to C++.

Examples

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Write a MATLAB function from which you can generate code. This example uses the function myadd that returns the sum of its inputs.

function c = myadd(a,b)
c = a + b;
end

Create a configuration object for MEX function generation.

cfg = coder.config('mex');

Change the values of the properties for which you do not want to use the default values. For example, enable just-in-time (JIT) compilation.

cfg.EnableJIT = true;

Generate code by using codegen. Pass the configuration object to codegen by using the -config option. Specify that the input arguments are scalar double.

codegen myadd -config cfg -args {1 1} -report

Alternative Functionality

To use default configuration parameter values for MEX function generation, instead of creating a configuration object, you can call codegen without specifying a configuration object or with the -config:mex option.

See Also

Functions

Objects

Topics

Introduced in R2011a

MATLAB Coder Documentation

Support