[Development] Announcing moc_combine
Joerg Bornemann
joerg.bornemann at qt.io
Tue May 31 18:13:18 CEST 2016
On 29/05/2016 18:05, Thiago Macieira wrote:
> I've just pushed a feature[1] to moc that makes it process multiple headers at
> the same time, producing only one output file, and a second feature[2] that
> "precompiles" a header. Since moc is single-threaded, this often means more
> wall-clock time than the previous case, but it's always less CPU time:
[...]
While this feature reduces the build time for full builds within a
measurable range, it drastically increases build time for incremental
builds. Changing just one Q_OBJECT header file results in full
regeneration of combined_moc.cpp.
Take for example:
touch src/widgets/dialogs/qprogressdialog.h
make
moc time without moc_combine: 0.8s
moc time with moc_combine: 15.6s
This feature is nice for source distributions but isn't suitable for
code being developed.
BR,
Joerg
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