While writing max ulong value, I added the "u" postfix. So compiler accepted it as ulong value (That's my interpretation if correct on compiler's side).

writeln( 18_446_744_073_709_551_615u );

But when I try to print out minimum value of long, compiler says
Error: signed integer overflow

writeln( -9_223_372_036_854_775_808 );

In case that is the wrong value, I checked it with writeln( long.min ); already.

Do I need to put a postfix for that number? I checked documentation by searching "dlang integer" etc, but couldn't have found any information/anything about postfix at all.

On 10/06/2015 08:16 AM, tcak wrote:
> While writing max ulong value, I added the "u" postfix.

Better to use U to be consistent with L (see below).

> But when I try to print out minimum value of long, compiler says
> Error: signed integer overflow
>
> writeln( -9_223_372_036_854_775_808 );

I would expect the following to work:

    writeln( -9_223_372_036_854_775_808L);

But it doesn't compile:

  Error: signed integer overflow

It looks like a compiler bug to me. If so, a very embarrassing one. :)

(You can use UL and LU as well.)

> Do I need to put a postfix for that number? I checked documentation by
> searching "dlang integer" etc, but couldn't have found any
> information/anything about postfix at all.

They go by "suffix". The officital documentation:

  http://dlang.org/lex.html#integerliteral

My short mention of them start at the section "The L suffix":

  http://ddili.org/ders/d.en/literals.html#ix_literals.literal

(They were missing in my index section. Adding now...)

Ali

On Tuesday 06 October 2015 17:39, Ali Çehreli wrote:

> I would expect the following to work:
> 
>      writeln( -9_223_372_036_854_775_808L);
> 
> But it doesn't compile:
> 
>    Error: signed integer overflow
> 
> It looks like a compiler bug to me. If so, a very embarrassing one. :)

https://issues.dlang.org/show_bug.cgi?id=8929

On Tuesday, October 06, 2015 15:16:12 tcak via Digitalmars-d-learn wrote:
> While writing max ulong value, I added the "u" postfix. So compiler accepted it as ulong value (That's my interpretation if correct on compiler's side).
>
> writeln( 18_446_744_073_709_551_615u );
>
> But when I try to print out minimum value of long, compiler says Error: signed integer overflow
>
> writeln( -9_223_372_036_854_775_808 );
>
> In case that is the wrong value, I checked it with writeln(
> long.min ); already.
>
> Do I need to put a postfix for that number? I checked documentation by searching "dlang integer" etc, but couldn't have found any information/anything about postfix at all.

L is the prefix to use, but it looks like there's a compiler bug here, because

long l = -9_223_372_036_854_775_807L;

compiles

and

long l = -9_223_372_036_854_775_808L;

doesn't, even though that's the same as long.min.

long l = -9_223_372_036_854_775_807UL;

compiles and does the right thing, though that's a pretty silly thing to have to do.

Actually, digging through bugzilla, it looks like it's already been reported:

https://issues.dlang.org/show_bug.cgi?id=8929

Though since C has the same problem, it's treated as an enhancement rather than a bug (which seems wrong to me). Apparently, the problem stems from the compiler processing the literal and _then_ applying the sign, and long.max is 9_223_372_036_854_775_807L. Apparently, -2L^^63 will work though.

All in all, it's probably not a big deal, since you should probably just being using long.min anyway, but this doesn't seem like particularly good behavior to me.

- Jonathan M Davis

Jonathan,

I saw this answered in another post: http://forum.dlang.org/post/gtaublmskqrhnbhoesex@forum.dlang.org

I.e., you can do long(-9223372036854775808UL) :)

Or long l = -9223372036854775808UL;

On Tuesday, 6 October 2015 at 15:16:13 UTC, tcak wrote:
> While writing max ulong value, I added the "u" postfix. So compiler accepted it as ulong value (That's my interpretation if correct on compiler's side).
>
> writeln( 18_446_744_073_709_551_615u );
>
> But when I try to print out minimum value of long, compiler says
> Error: signed integer overflow
>
> writeln( -9_223_372_036_854_775_808 );
>
> In case that is the wrong value, I checked it with writeln( long.min ); already.
>
> Do I need to put a postfix for that number? I checked documentation by searching "dlang integer" etc, but couldn't have found any information/anything about postfix at all.

See above ^^ :D