Nice post as always, Rick! During my days as a SAS/STAT developer, I used many of the constants that the CONSTANT function provides. Of course, as a developer, we accessed them in a different way. Perhaps you could convince our friends in BASE/SAS documentation to provide a program that provides an easy way for users to see all of the constants that the function provides since they can't all be documented because values can radically change on different systems.

options missing= ' ';
data Constants;
length Const $16;
format Value Base Best16.;
input Const @@;
if index(Const, "EXACT") then do;
do Bytes = 2 to 8;
Value = constant(Const, bytes);
output;
end;
end;
else if index(Const, "LOG") then do;
do base = 2, constant('E'), 10;
Value = constant(Const, base);
output;
end;
end;
else do;
Value = constant(Const);
output;
end;
datalines;
E EULER GOLDEN PI EXACTINT BIG BIGRECIP LOGBIG LOGBIGRECIP SQRTBIG SMALL
SMALLRECIP LOGSMALL LOGSMALLRECIP SQRTSMALL MACEPS LOGMACEPS SQRTMACEPS
;

proc print noobs; run;