Call C from MATLAB

Directly call C library functions from MATLAB^® R2021b or earlier, using calllib function

A shared library is a collection of functions dynamically loaded by an application at run time. The MATLAB interface supports libraries containing functions defined in C header files. To call functions in C++ libraries, use the interface described in Call C++ from MATLAB.

Functions

`loadlibrary`	Load C shared library into MATLAB
`unloadlibrary`	Unload shared C library from memory
`calllib`	Call function in C shared library
`libfunctions`	Return information on functions in shared C library
`libfunctionsview`	Display shared C library function signatures in window
`libisloaded`	Determine if shared C library is loaded
`libpointer`	Pointer object for use with shared C library
`libstruct`	Convert MATLAB structure to C-style structure for use with shared C library

Classes

lib.pointer Pointer object compatible with C pointer

Topics

Call Functions in C Library Loaded with loadlibrary

How to call functions in external, shared C libraries from MATLAB using calllib.
- Load and Unload C Shared Library
- View Library Functions
- Invoke Library Functions
- Shared Library shrlibsample
- Iterate Through lib.pointer Object
Pass Arguments to Shared C Library Functions

How to construct MATLAB arguments compatible with the argument types found in the library functions.
- Pass String Arguments Examples
- Pass Arrays Examples
- Pass Enumerated Types Examples
Represent Pointer Arguments in C Shared Library Functions

How to use libpointer to pass arguments by reference.
- Pass Pointers Examples
Represent Structure Arguments in C Shared Library Functions

Requirements for passing a MATLAB structure to an external library function.
- Pass Structures Examples
- Explore libstruct Objects
MATLAB Prototype Files
How to modify C header file information.

Troubleshooting

Limitations to Shared Library Support

C language features not supported.

Limitations Using Structures

Rules for using C language structures in a shared library.

Loading Library Errors

Errors occur when the shared library is not a valid library.

No Matching Signature Error

This error occurs when you call a function without the correct input or output arguments, or if there is an error in the function signature in the header file.

MATLAB Terminates Unexpectedly When Calling Function in Shared Library

Some shared libraries, compiled as Microsoft^® Windows^® 32-bit libraries, use a calling convention that is incompatible with the default MATLAB calling convention.