External Interfaces/API

Reading and Writing MAT-Files

The save command in MATLAB saves the MATLAB arrays currently in memory to a binary disk file called a MAT-file. The term MAT-file is used because these files have the extension .mat. The load command performs the reverse operation. It reads the MATLAB arrays from a MAT-file on disk back into MATLAB workspace.

A MAT-file may contain one or more of any of the data types supported in MATLAB 5 or later, including strings, matrices, multidimensional arrays, structures, and cell arrays. MATLAB writes the data sequentially onto disk as a continuous byte stream.

MAT-File Interface Library

The MAT-file interface library contains a set of routines for reading and writing MAT-files. You can call these routines from within your own C and Fortran programs. We recommend that you use these routines, rather than attempt to write your own code, to perform these operations. By using the routines in this library, you will be insulated from future changes to the MAT-file structure.

The MAT-file library contains routines for reading and writing MAT-files. They all begin with the three-letter prefix mat. These tables list all the available MAT-functions and their purposes.

Table 6-1: C MAT-File Routines  

MAT-Function	Purpose
matOpen	Open a MAT-file
matClose	Close a MAT-file
matGetDir	Get a list of MATLAB arrays from a MAT-file
matGetFp	Get an ANSI C file pointer to a MAT-file
matGetVariable	Read a MATLAB array from a MAT-file
matPutVariable	Write a MATLAB array to a MAT-file
matGetNextVariable	Read the next MATLAB array from a MAT-file
matDeleteVariable	Remove a MATLAB array from a MAT-file
matPutVariableAsGlobal	Put a MATLAB array into a MAT-file such that the load command will place it into the global workspace
matGetVariableInfo	Load a MATLAB array header from a MAT-file (no data)
matGetNextVariableInfo	Load the next MATLAB array header from a MAT-file (no data)

Table 6-2: Fortran MAT-File Routines  

MAT-Function	Purpose
matOpen	Open a MAT-file
matClose	Close a MAT-file
matGetDir	Get a list of MATLAB arrays from a MAT-file
matGetVariable	Get a named MATLAB array from a MAT-file
matGetVariableInfo	Get header for named MATLAB array from a MAT-file
matPutVariable	Put a MATLAB array into a MAT-file
matPutVariableAsGlobal	Put a MATLAB array into a MAT-file
matGetNextVariable	Get the next sequential MATLAB array from a MAT-file
matGetNextVariableInfo	Get header foro next sequential MATLAB array from a MAT-file
matDeleteVariable	Remove a MATLAB array from a MAT-file

Exchanging Data Files Between Platforms

Finding Associated Files