Should I convert FORTRAN code to C?

[Doug Gwyn]

In article <3946 at pasteur.Berkeley.Edu> faustus at ic.Berkeley.EDU (Wayne A. Christopher) writes:
>The best reason NOT to allow a compiler to expand standard functions in-line
>is that you can't substitute your own to fix a bug in the standard version.
>I've had to do this a number of times with bug-prone functions like floor()
>(too many versions round towards zero instead of down).

NO NO NO -- Don't do this!

Assuming for the sake of argument that some implementation has a floor()
function like that, it is quite possible that some of the other math
library routines actually depend on that behavior.  If you change it,
you will break other routines in possibly subtle ways.

A much better solution to this particular problem would be:

	#define	Floor	my_floor	/* or "floor", if it works right */
	extern double Floor(double);

	/* ... use "Floor" instead of "floor" ... */

	double my_floor(register double x)	/* adjust for floor() bug */
		{
		extern double floor(double);	/* from math library */
		register double xf = floor(x);

		return x >= 0 ? xf : x == xf ? x : xf - 1;
		}

Also report the floor() bug to the library implementor.