C MEX File Applications

Write C programs that work with MATLAB^® R2017b or earlier, using mxArray

You can call your own C or C++ programs from the MATLAB command line as if they were built-in functions. These programs are called MEX functions and the function name is the MEX file name. MEX functions are not appropriate for all applications. MATLAB is a high-productivity environment whose specialty is eliminating time-consuming, low-level programming in compiled languages. In general, do your programming in MATLAB. Do not use MEX functions unless your application requires it.

To create a MEX function, write your programs using MATLAB APIs. The functions in these libraries facilitate the transfer of data between MEX functions and the workspace. To choose a MATLAB API, consider the following.

MathWorks recommends that you create MEX functions using modern C++ features, as defined in the MATLAB Data API. For more information, see C++ MEX Applications.
If your MEX functions must run in MATLAB R2017b or earlier, or if you prefer to work in the C language, then use functions in the C Matrix API and the C MEX API. These APIs use the MATLAB mxArray data structure. The functions and topics on this page are based on mxArray.

Note

Choose functions from either the C Matrix API or the MATLAB Data API; you cannot mix functions from these APIs.

Build your source file into an executable program using the mex function. You can also share the MEX file with other MATLAB users.

For information about writing S-functions, see your Simulink^® documentation.

To call a MEX function that someone else created, see MEX File Functions.

If you have a C/C++ program and want to call MATLAB functions from the program, then use one of the engine APIs.

If you want to read and write MATLAB data from C/C++ programs, then use the MATLAB C API to Read MAT-File Data.

Functions

`mex`	Build MEX function or engine application
`dbmex`	Enable MEX-file debugging on UNIX platforms

C MEX API

`mexFunction`	Entry point to C/C++ MEX function built with C Matrix API
`mexFunctionName`	Name of current MEX function
`mexAtExit`	Register function to call when MEX function clears or MATLAB terminates
`mexCallMATLAB`	Call MATLAB function, user-defined function, or MEX function
`mexCallMATLABWithTrap`	Call MATLAB function, user-defined function, or MEX-file and capture error information
`mexEvalString`	Execute MATLAB command in caller workspace
`mexEvalStringWithTrap`	Execute MATLAB command in caller workspace and capture error information
`mexGetVariable`	Copy of variable from specified workspace
`mexGetVariablePtr`	Read-only pointer to variable from another workspace
`mexPutVariable`	Array from MEX function into specified workspace
`mexGet`	Value of specified graphics property
`mexSet`	Set value of specified graphics property
`mexPrintf`	ANSI C PRINTF-style output routine
`mexErrMsgIdAndTxt`	Display error message with identifier and return to MATLAB prompt
`mexWarnMsgIdAndTxt`	Warning message with identifier
`mexIsLocked`	Determine if MEX-file is locked
`mexLock`	Prevent clearing MEX-file from memory
`mexUnlock`	Allow clearing MEX-file from memory
`mexMakeArrayPersistent`	Make array persist after MEX file completes
`mexMakeMemoryPersistent`	Make memory allocated by MATLAB software persist after MEX-function completes