Function aliasing

If any aliased function is to be used or provided by the thorn then the prototype must be declared with the form:

<return_type> FUNCTION <alias>(<arg1_type> <intent1> [ARRAY] <arg1>, ...)

The <return_type> must be either void, CCTK_INT or CCTK_REAL. The keyword SUBROUTINE is equivalent to void FUNCTION. The name of the aliased function <alias> must contain at least one uppercase and one lowercase letter and follow the C standard for function names. The type of each argument, <arg*_type> must be a CCTK type in INT,REAL,STRING,POINTER. The intent of each argument, <intent*> must be either IN or OUT. An argument should only be modified if it is declared to have intent OUT. If the argument is an array then the prefix ARRAY should also be given.

If the argument <arg*> is a function pointer then the argument itself (which will preceded by the return type) should be

CCTK_FPOINTER <function_arg1>(<arg1_type> <intent1> <arg1>, ...)

Function pointers may not be nested.

If an aliased function is to be required then the block

REQUIRES FUNCTION <alias>

is required.

If an aliased function is to be (optionally) used then the block

USES FUNCTION <alias>

is required.

If a function is provided then the block

PROVIDES FUNCTION <alias> WITH <provider> LANGUAGE <providing_language>

is required. As with the alias name, <provider> must contain at least one uppercase and one lowercase letter and follow the C standard for function names. Currently the only supported values of <providing_language> are C and Fortran.