[MacPorts] #46951: finance/bitcoin: Problems compiling against Qt4
noreply at macports.org
Fri Apr 26 04:54:17 UTC 2019
#46951: finance/bitcoin: Problems compiling against Qt4
Reporter: easye | Owner: easye
Type: enhancement | Status: new
Priority: Normal | Milestone:
Component: ports | Version:
Resolution: | Keywords:
Port: bitcoin |
Comment (by kencu):
This error occurs because the older `moc` program in `qt4`, which is
essentially a preprocessor, does not understand the more complicated macro
substitution that is being used in certain parts of newer versions of
`boost` has decided this is not their error to fix. `qt5` has an upgrade
`moc` program and it understands the fancy business going on in the
`boost` headers. It is reported that this improved `moc` will never be
backported to `qt4`.
The only solution is to block the problematic boost header from being
preprocessed by `qt4`'s `moc`. If there are not too many instances of
`#include <boost/xyz>` then you can wrap the header with
and that basically makes `moc` skip over the header, but somehow it still
works out in the end that the header is used.
If you have a lot of these `#include <boost/xyx.h>` then that approach can
get mighty tedious quickly.
%3Acomment-tabpanel#comment-192942 discussion] suggests you can wrap `moc`
and add a define to it's implementation to make `moc` skip the problematic
QMAKE_MOC = /path/to/moc -DBOOST_TT_HAS_OPERATOR_HPP_INCLUDED
For my purposes, I just hacked the boost header directly for the duration
of the problem build. This header that was causing all the errors for me
was this one:
so I added this at the top:
and this at the bottom
and the build completed without a hiccup.
Now -- clearly I should remove that guard after the `qt4` build has
completed, to get back to stock `boost` headers. But I will admit I'm
rather tempted to just leave it there, because it looks like it can do no
harm (what else is ever going to define `Q_MOC_RUN` other than `moc`)...
but I guess `qt5`'s `moc` might, so there's a reason to remove it.
I have been trying to come up with a fancy method to wrap that header in a
block automatically, and so far, I can't.
But anyway, there are several workarounds for the `BOOST_JOIN` problem
Ticket URL: <https://trac.macports.org/ticket/46951#comment:8>
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