IMHO the error is in the coding ... :-)

the REGINA REXX manual - in the D2C and D2X paragraphs - state in clear words that

... Integer must be a whole number under the current settings of NUMERIC,

it is not effected by the precision of the built-in functions.

( for D2C in a slightly different wording )

and datatype(n,W)=0 tells that n is NOT a

... valid REXX whole number under the current setting of NUMERIC.

but now somebody might feel that a different error is coming up....

and the FIRST DISPLAY of n should have been in EXP format

because of the assigning of a 10 digits number to a variable when a NUMERIC DIGITS 9 is in effect !

well, the feeling is wrong ...

REXX enforces the NUMERIC DIGITS constraint only when doing <arithmetics>,

until then the <thing> is just a string made of all numbers

regards

Enrico Sorichetti

PS.

al least ooRexx chokes in a slightly more CONSISTENT and descriptive way ...

( also on the first iteration )

===================1====================

digits= 9

n=3735928559

datatype(n)=NUM

datatype(n,W)=0

16 *-* say 'done as' d2x(n)

REX0093E: Error 93 running /Users/enrico/ztests/t.rx line 16: Incorrect call to method

REX0456E: Error 93.928: D2X value must be a valid whole number; found "3735928559"