Two modifiers to the structured comments indicate special
behavior of the function. The modifiers must come after the character that
indicates a routine, macro, or documentation.
The modified C indicates that this routine is available only in C (and
not from Fortran). If this modifier is present, bfort will not
generate a wrapper for the routine. For example, a routine that returns a
pointer to memory cannot be called from standard Fortran 77, so its
structured comment should be
/*@C .... @*/The other modifier is X; this indicates that the routine requires the X11 Window System. This is used by bfort to provide an #ifdef around the call in case X11 include files are not available.
The modifiers C and X may be used together and may be specified in either order (i.e., CX or XC).