On Sunday, 27 March 2022 at 17:46:54 UTC, Anonymouse wrote:
> I installed Git for Windows which comes with the Msys terminal, and I noticed writeln lines aren't being flushed on linebreaks

If the C library thinks it is talking to a pipe, it will switch to block buffering instead of line buffering. It must just think msys is a pipe (since it probably is under the hood).

Normally the IOLBF thing does help there - that means line buffering - but my recommentation is to explicitly call `stdout.flush()` any time it is important in your code. Then you aren't depending on the relatively hidden config value.

Don't know if this is OT here.

On Sunday, 27 March 2022 at 18:09:30 UTC, Adam D Ruppe wrote:
> If the C library thinks it is talking to a pipe, it will switch to block buffering instead of line buffering. It must just think msys is a pipe (since it probably is under the hood).

while compiling a project with make -j6 I see this:

[...]
decimal/decimal.d(13080): decimal/decimal.d(13080): Deprecation: Deprecation: UUssagea goef  otfh et h`e `bodbyody` k`e ykweoyrwdo rids  idse pdreepcraetceadt.e dU.s eU s`e `dodo` i`n sitnesatde.a
d.
decimal/decimal.d(13217): decimal/decimal.d(13217): Deprecation: Deprecation: UUssaaggee  ooff  tthhee  ``bbooddyy``  kkeeyywwoorrdd  iiss  ddeepprreeccaatteedd..  UUssee  ``ddoo``  iinnsstteeaadd..

decimal/decimal.d(13239): Deprecation: decimal/decimal.d(13239): UDeprecation: sageU soafg et hoef  `the b`odybo`d ykey`w okredy wiosr dd eipsr edceaptreedc.a tUesde.  `Use d`o`d oins`t eiands.t
ead.
decimal/decimal.d(13327): decimal/decimal.d(13327): Deprecation: Deprecation: UUssaaggee  ooff  tthhee  ``bbooddyy``  kkeeyywwoorrdd  iiss  ddeepprreeccaatteedd..  UUssee  ``ddoo``  iinnsstteeaadd..

The write calls are mostly unbuffered as strace reveals:

29680 write(2, "\33[1m", 4)             = 4
29680 write(2, "decimal/decimal.d(471): ", 24) = 24
29680 write(2, "\33[1;36m", 7)          = 7
29680 write(2, "Deprecation: ", 13)     = 13
29680 write(2, "\33[m", 3)              = 3
29680 write(2, "U", 1)                  = 1
29680 write(2, "s", 1)                  = 1
29680 write(2, "a", 1)                  = 1
29680 write(2, "g", 1)                  = 1
29680 write(2, "e", 1)                  = 1
29680 write(2, " ", 1)                  = 1
29680 write(2, "o", 1)                  = 1
29680 write(2, "f", 1)                  = 1
29680 write(2, " ", 1)                  = 1
29680 write(2, "t", 1)                  = 1
29680 write(2, "h", 1)                  = 1
29680 write(2, "e", 1)                  = 1
29680 write(2, " ", 1)                  = 1

> Normally the IOLBF thing does help there - that means line buffering - but my recommentation is to explicitly call `stdout.flush()` any time it is important in your code. Then you aren't depending on the relatively hidden config value.

Shall I file an issue for this?