Why do I get an assertion violation when I port my 32-bit FORTRAN MEX source to a 64-bit MATLAB 7.6 (R2008a) ?

I have an existing FORTRAN MEX source code which compiles and works fine on a 32-bit MATLAB. This source also compiles fine on 64-bit MATLAB, but it fails when I try to run it.

Answer 1

[MathWorks Support Team]

Some legacy FORTRAN code use the following syntax to define the MEXFUNCTION:

SUBROUTINE MEXFUNCTION(NLHS, PLHS, NRHS, PRHS)

INTEGER PLHS(*), PRHS(*)

INTEGER NLHS, NRHS

This might compile and execute on a 32-bit platform, however, the recommended syntax is to use MWPOINTER as shown below (for any platform).

This is essential for the MEX file to execute successfully on a 64-bit platform.

SUBROUTINE MEXFUNCTION(NLHS, PLHS, NRHS, PRHS)

MWPOINTER PLHS(*), PRHS(*)

INTEGER NLHS, NRHS