How you do *unescape* a string... and some weirdness

[jyavenard]

Hello

In my qmake file, I added to a variable the following:

MYSQLIBS = "$$system(mysql_config --libs)"
MYSQLIBS ~= s/-arch +[a-z0-9_]+//g #remove all "-arch arg" settings
LIBS += MYSQLIBS

Unfortunately here, LIBS in the generated Makefile now contains:
LIBS = $(SUBLIBS) -L/usr/local/mythtv-trunk/lib -Wl,-Bsymbolic-functions\ -rdynamic\ -L/usr/lib/mysql\ -lmysqlclient


see that all the space have been escaped.

What I would like to end-up with is:
LIBS = $(SUBLIBS) -L/usr/local/mythtv-trunk/lib -Wl,-Bsymbolic-functions -rdynamic -L/usr/lib/mysql -lmysqlclient

Otherwise the following would fail to compile under linux.

Now that brings me to another weirdness.
The reason I did:

MYSQLIBS = "$$system(mysql_config --libs)"
instead of:
MYSQLIBS = $$system(mysql_config --libs)

It's because otherwise, the regex replacement that follow would have otherwise no effect at all, and it only works if the variable has been placed in quote.

Another annoyance I do not know how to deal with is: on mac, some linker settings are in the form:
-arch arg
where arg can be i386, x86_64, ppc7400, ppc64

The problem is how qmake deals when adding those parameters.
If I have

EXTRA_LFLAGS = -arch i386
and
QMAKE_LFLAGS = -arch i386

doing:

QMAKE_LFLAGS += $$EXTRA_LFLAGS

The generated makefile will contain:
LFLAGS = -arch i386 -arch

the 2nd i386 has been dropped. Compilation *will* failt
According to the qmake documentation, += shouldn't drop items, that's what *= does:
The *= operator adds a value to the list of values in a variable, but only if it is not already present. This prevents values from being included many times in a variable. For example:

Now I could do:
EXTRA_FLAGS = "-arch i386"
QMAKE_LFLAGS += $$EXTRA_FLAGS

but then I end up in the Makefile with:
LFLAGS = -arch i386 -arch\ i386

which will not always work depending on how the linker is called.

Any advice on how to resolve the above issues would be *extremely* appreciated.

Thank you in advance.
Kind regards
JY

[ChrisW67]

Each QMake variable is a list. The regex line in your example works on each value in the list in isolation. When you do not quote the system() output the list gets a populated with elements by splitting on white space. The "-arch" and "arg" go into separate list elements, neither of which matches your regex

When you quote (or $$quote()) the system call output you put a single value in the list. Your qmake regex now works but anywhere the single list entry is output into a command line the spaces will be quoted as you have seen.

I'd be inclined to do this on UNIX-ish systems:

MYSQLIBS = $$system(mysql_config --libs | sed -r 's/-arch +[a-z0-9_]+//g')
LIBS += MYSQLIBS

MYSQLIBS = $$system(mysql_config --libs | sed -r 's/-arch +[a-z0-9_]+//g')
LIBS += MYSQLIBS

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to remove the -arch arg before qmake sees it.

However: you can also use the [wiki=Undocumented_qmake#Undocumented_functions]undocumented split()[/wiki] function thus:

MYSQLIBS = $$quote($$system(mysql_config --libs))
MYSQLIBS ~= s/-arch +[a-z0-9_]+//g #remove all "-arch arg" settings
MYSQLIBS = $$split(MYSQLIBS," ")
LIBS += $$MYSQLIBS

MYSQLIBS = $$quote($$system(mysql_config --libs))
MYSQLIBS ~= s/-arch +[a-z0-9_]+//g #remove all "-arch arg" settings
MYSQLIBS = $$split(MYSQLIBS," ")
LIBS += $$MYSQLIBS

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For the QMAKE_LFLAGS problem. I see the same effect on Linux when unquoted and I am guessing that internally the unique() function is used on the QMAKE_LFLAGS variable. When I do this:

EXTRA_FLAGS = "-arch i386"
QMAKE_LFLAGS += $$EXTRA_FLAGS

EXTRA_FLAGS = "-arch i386"
QMAKE_LFLAGS += $$EXTRA_FLAGS

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the second "-arch i386" completely disappears from the Makefile.

Why do you need to duplicate this entry? Will the linker accept "-arch:386" or "-arch=386"?