What is the relationship between GPC and IEEE 754 floating point?
THINK and CW (both Mac dialects) allowed e.g.
a := Inf; a := -Inf; a := NaN;
but these are rejected by GPC as undeclared identifiers.
I can get the same effect by e.g.
a := MaxReal * 2.0; {inf} a := 0.0 / 0.0; {nan}
but this seems like a hack.
Also, the old SANE (Apple's most excellent 754 implementation from way back--I think the guru Kaplan was involved, as he was with the also-most-excellent HP-15c pocket calculator) allowed returning specific numeric codes to allow determining what caused a NaN. I remember writing an arctan2 function and in the case of arctan2(0.0, 0.0), I assigned a returm value of something like NaN(85), which was somehow a NaN even though the construct looks like a function. I _think_ I could then query that particular NaN to get a clue about where it arose. I lost this when porting to CW, however.
Anyway, just wondering.
Jerry