Tables of MEX Function Source Code Examples

Note

It is recommended to use clibPublishInterfaceWorkflow to write code in MATLAB^® R2023a or later to directly call functions in C/C++ libraries. Alternatively, to write MEX functions using modern C++ features and the MATLAB Data API for C++, see Write C++ Functions Callable from MATLAB (MEX Files).

The following tables contain lists of source code files for creating example MEX functions using mxArray in the C Matrix API. Use these examples as a starting point for creating your own MEX functions. The tables contain the following information.

• Example Name - a link that opens the source file in MATLAB Editor for your convenience. You can use any code development editor to create source MEX files.

• Example Subfolder - the subfolder of matlabroot/extern/examples containing the example. Use this subfolder name when copying the file to a writable folder.

• Description - describes the example.

• More Information - a link to a topic describing or using the example, or to the API function used in the example.

Getting Started

Use the mex command to build the examples. Make sure that you have a compiler installed that MATLAB supports. To verify the compiler selected for the source code language lang, type:

mex -setup lang

Copy the file to a writable folder on your path using the following command syntax. filename is the name of the example, and foldername is the subfolder name.

copyfile(fullfile(matlabroot,"extern","examples","foldername","filename"),".","f")

For example, to copy arrayProduct.c, type:

copyfile(c,".","f")

C, C++, and Fortran MEX Functions

To build an example MEX function in MATLAB or at your operating system prompt, use this command syntax. filename is the example name, and release-option specifies the API used by the example. For information about the MATLAB APIs, see Choosing MEX Applications.

mex -v -release-option filename

Example Name	Example Subfolder	Description	More Information
arrayFillGetPr.c	refbook	Fill mxArray using mxGetDoubles.	Fill mxArray in C MEX Function
arrayFillSetData.c	refbook	Fill mxArray with non-double values.	Fill mxArray in C MEX Function
arrayFillSetPr.c	refbook	Fill mxArray using mxSetDoubles to allocate memory dynamically.	Fill mxArray in C MEX Function
arrayFillSetComplexPr.c	refbook	Fill mxArray using mxSetComplexDoubles to allocate memory dynamically.	Fill mxArray in C MEX Function
arrayProduct.c	mex	Multiply a scalar times 1xN matrix.	Create C MEX Function arrayProduct
arrayProduct.cpp	cpp_mex	Same as arrayProduct.c, using the MATLAB Data API for C++.	C++ MEX Functions
arraySize.c	mex	Illustrate memory requirements of large mxArray.	Handling Large mxArrays in C MEX Functions
complexAdd.F	refbook	Add two complex double arrays.
convec.c convec.F	refbook	Pass complex data.	Handle Complex Data in C MEX Function
dblmat.F compute.F	refbook	Use of Fortran %VAL.
doubleelement.c	refbook	Use unsigned 16-bit integers.	Handle 8-, 16-, 32-, and 64-Bit Data in C MEX Function
explore.c	mex	Identify data type of input variable.	Work with mxArrays
findnz.c	refbook	Use N-dimensional arrays.	Manipulate Multidimensional Numerical Arrays in C MEX Functions
fulltosparseIC.c fulltosparse.c fulltosparse.F, loadsparse.F	refbook	Populate a sparse matrix.	Handle Sparse Arrays in C MEX Function
matsq.F	refbook	Pass matrices in Fortran.
matsqint8.F	refbook	Pass non-double matrices in Fortran.
mexatexit.c mexatexit.cpp	mex	Register an exit function to close a data file.	C++ File Handling Example
mexcallmatlab.c	mex	Call built-in MATLAB disp function.
mexcallmatlabwithtrap.c	mex	How to capture error information.
mexcpp.cpp	mex	Illustrate C++ language features in a MEX function built with the C Matrix API.	C++ Class Example
mexevalstring.c	mex	Use mexEvalString to assign variables in MATLAB.	mexEvalString
mexfunction.c	mex	How to use mexFunction.	mexFunction
mxgetproperty.c	mex	Use mxGetProperty and mxSetProperty to change the Color property of a graphic object.	mxGetProperty and mxSetProperty
mexgetarray.c	mex	Use mexGetVariable and mexPutVariable to track counters in the MEX function and in the MATLAB global workspace.	mexGetVariable and mexPutVariable
mexgetarray.cpp		Same as mexgetarray.c, using getVariable and setVariable in the MATLAB Data API for C++.	Set and Get MATLAB Variables from MEX
mexlock.c mexlockf.F	mex	How to lock and unlock a MEX function.	mexLock
mxcalcsinglesubscript.c	mx	Demonstrate MATLAB 1-based matrix indexing versus C 0-based indexing.	mxCalcSingleSubscript
mxcreatecellmatrix.c mxcreatecellmatrixf.F	mx	Create 2-D cell array.	Create 2-D Cell Array in C MEX Function
mxcreatecharmatrixfromstr.c	mx	Create 2-D character array.	mxCreateCharMatrixFromStrings
mxcreatestructarray.c	mx	Create MATLAB structure from C structure.	mxCreateStructArray
mxcreateuninitnumericmatrix.c	mx	Create an uninitialized mxArray, fill with local data, and return.	mxCreateUninitNumericMatrix
mxgeteps.c mxgetepsf.F	mx	Read MATLAB eps value.	mxGetEps
mxgetinf.c	mx	Read inf value.	mxGetInf
mxgetnzmax.c	mx	Display number of nonzero elements in a sparse matrix and maximum number of nonzero elements it can store.	mxGetNzmax
mxisclass.c	mx	Check if array is member of specified class.	mxIsClass
mxisfinite.c	mx	Check for NaN and infinite values.	mxIsFinite
mxislogical.c	mx	Check if workspace variable is logical or global.	mxIsLogical
mxisscalar.c	mx	Check if input variable is scalar.	mxIsScalar
mxmalloc.c	mx	Allocate memory to copy a MATLAB char array to a C-style string.	mxMalloc
mxsetdimensions.c mxsetdimensionsf.F	mx	Reshape an array.	mxSetDimensions
mxsetnzmax.c	mx	Reallocate memory for sparse matrix and reset values of pr, pi, ir, and nzmax.	mxSetNzmax
passstr.F	refbook	Pass C character matrix from Fortran to MATLAB.
phonebook.c	refbook	Manipulate structures and cell arrays.	Pass Structures and Cell Arrays in C MEX Function
phonebook.cpp	cpp_mex	Same as phonebook.c, using the MATLAB Data API for C++.	C++ MEX Functions
revord.c revord.F	refbook	Copy MATLAB char array to and from C-style string.	Pass Strings in C MEX Function
sincall.c sincall.F, fill.F	refbook	Create mxArray and pass to MATLAB sin and plot functions.
timestwo.c timestwo.F	refbook	Demonstrate common workflow of MEX function.	Pass Scalar Values in C MEX Function
xtimesy.c xtimesy.F	refbook	Pass multiple parameters.
yprime.c yprimef.F, yprimefg.F	mex	Solve simple three body orbit problem.
yprime.cpp	cpp_mex	Same as yprime.c, using the MATLAB Data API for C++.	C++ MEX Functions

MEX Functions Calling Fortran Subroutines

The examples in this table call a LAPACK or BLAS function from a MEX function. The examples link to one or both of the Fortran libraries mwlapack and mwblas. To build the MEX function, follow the instructions in the topics listed in the More Information column.

Example Name	Example Subfolder	Description	More Information
dotProductComplexIC.c dotProductComplexIC.F dotProductComplex.c	refbook	Handle Fortran complex return type for function called from a C or Fortran MEX function. dotProductComplexIC.c and dotProductComplexIC.F use the interleaved complex API. dotProductComplex.c uses the separate complex API.	Handle Fortran Complex Return Type — dotProductComplex
matrixDivide.c	refbook	Call a LAPACK function.	Preserve Input Values from Modification
matrixDivideComplex.c	refbook	Call a LAPACK function with complex numbers.	Pass Complex Variables — matrixDivideComplex
matrixMultiply.c	refbook	Call a BLAS function.	Pass Arguments to Fortran Functions from C/C++ Programs
utdu_slv.c	refbook	Use LAPACK for symmetric indefinite factorization.	Symmetric Indefinite Factorization Using LAPACK — utdu_slv