Error code returned from C library functions

[susnak]

From @susnak on April 17, 2015 8:34

• [x] Decide what the error code should be and how the errors should be checked.
• [ ] Modify the computational functions in the C backend library to return error code.
• [ ] Check the returned code in MEX and OCT files.

This will at least immediately identify that the error comes from the backend library.

Possible return types will be stored as enum ltfatStatus

typedef enum { ltfatUnspecErr = 1, ltfatMemAlocErr = 2, ltfatNoErr = 0, ... } ltfatStatus;

Copied from original issue: ltfat/ltfat#35