You should show the entire code you are using, not just a snippet of it. Also, the fact that you have a typo in the function name (which would have caused a LINK error) tells me that you typed this code in manually instead of copying and pasting it. Please don't do that! Just copy and paste the actual code.
That being said, I assume you have done something like this:
mxArray *pMatr = nullptr;
char *cData[10];
cData[0] = mxArrayToString( something );
pMatr = mxCreateCharMatrixFromStrings(345, (const char**)cData[0]);
The variable name cData does in fact reduce to type (char **) when used in an expression, so it is already of the correct type to simply pass in directly as the 2nd argument. And in fact that is precisely what mxCreateCharMatrixFromStrings is expecting. Also, the 345 will cause a seg fault since there are only 10 physical elements in the cData array. So it needs to be something like this:
mxArray *pMatr = nullptr;
char *cData[344];
cData[0] = mxArrayToString( something );
// other code here to assign cData[1], cData[2], ..., cData[343]
pMatr = mxCreateCharMatrixFromStrings(344, cData);
Also note that in R2016b and earlier, the allocated memory from the mxArrayToString( ) call is not on the garbage collection list. So you would have to manually mxFree( ) each individual cData element to avoid memory leaks.
