How to get function calling function from a MEX file - matlab

Question

I have a MEX function and I need to get the name of the function which called this MEX function from Matlab. Is there a way how to do it?
I have tried
mexCallMatlab(...,"dbstack")
but, it returns an empty result, because it is probably run in the workspace.
Yes, I know I could pass the function name directly as an argument, but that is not an option for me.

Answer 1

Calling "dbstack" using "mexCallMATLAB" from within the MEX function should do the trick. Just need to be a little careful when converting the output of "dbstack", which is a MATLAB struct, into a string. This is the C MEX code
#include "mex.h"
void mexFunction(int nlhs, mxArray *plhs[], int nrhs,
const mxArray *prhs[]) {
mxArray *mxArr[1];
mexCallMATLAB(1, mxArr, 0, NULL, "dbstack");
char *funcName = mxArrayToString(mxGetField(mxArr[0], 0, "name"));
printf("Function name = %s\n", funcName);
}
This is the MATLAB function calling the MEX function.
function callMyMex()
myMex();
end
When you run the "callMyMex" function, you should see the output:
Function name = callMyMex

Answer 2

If you run dbstack in the base workspace, the struct will indeed be empty. Here's how I tested it using mexCallMATLAB:
testMEX.cpp
#include "mex.h"
void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
mxArray *dbStruct;
mexCallMATLAB(1, &dbStruct, 0, NULL, "dbstack");
plhs[0] = mxDuplicateArray(dbStruct);
if (mxIsEmpty(dbStruct) || mxGetNumberOfFields(dbStruct) != 3) {
mexErrMsgTxt("dbstack not available from base workspace");
return;
}
mxArray *callerFileName = mxGetField(dbStruct, 0, "file");
char *fileStr = mxArrayToString(callerFileName);
mxArray *callerFunctionName = mxGetField(dbStruct, 0, "name");
char *funStr = mxArrayToString(callerFunctionName);
mxArray *callerLineNum = mxGetField(dbStruct, 0, "line");
int lineNum = static_cast<int>(mxGetScalar(callerLineNum));
mexPrintf("File: %s\n",fileStr); mxFree(fileStr);
mexPrintf("Function: %s\n", funStr); mxFree(funStr);
mexPrintf("Line: %d\n", lineNum);
}
testFun.m
function s = testFun()
s = testMEX;
Output
>> s = testMEX
Error using testMEX
dbstack not available from base workspace
>> s = testFun
File: testFun.m
Function: testFun
Line: 3
s =
file: 'testFun.m'
name: 'testFun'
line: 3