MEX application: integer value is kept in memory between runs

If I create the following C file:

#include "mex.h"

unsigned int inputCounter = 0;

void mexFunction(int nlhs, mxArray *plhs[], int nrhs,
        const mxArray *prhs[])
{
    mexPrintf("inputCounter = %d\n", inputCounter);
    inputCounter ++;
}

And compile and run it in Matlab with

mex MexIntegerInit.c
MexIntegerInit
MexIntegerInit
MexIntegerInit

I get the following output:

Building with 'MinGW64 Compiler (C)'.
MEX completed successfully.
inputCounter = 0
inputCounter = 1
inputCounter = 2

However, if I compile outside of Matlab with the same compiler (MinGW64), and run it as a standalone without re-compiling between runs, the value is not incremented.

Is this undefined behavior?

Answer 1

[Walter Roberson]

no the behaviour is defined . When called inside MATLAB it is being called as a subroutine of the MATLAB process which continues to exist after the call. When called standalone each call creates a process , runs, and terminates returning the memory to the operating system .