Fails to build with gcc-7

[Mattia Rizzolo]

As it has been reported in debian in https://bugs.debian.org/853453#8 - build log available there.

I think it has to do with this change: https://gcc.gnu.org/gcc-7/porting_to.html#cmath

relevant failure line (but there are others, see the log):

/src/ui/tools/flood-tool.cpp:253:119: error: call of overloaded 'abs(unsigned int)' is ambiguous
             diff += abs(static_cast<int>(amc ? unpremul_alpha(bmc, amc) : 0) - (amop ? unpremul_alpha(bmop, amop) : 0));

[Alex Valavanis (valavanisalex)]

Sounds like a fairly straightforward fix. I'll take a look.

[Alex Valavanis (valavanisalex)]

More specifically, it's this issue: https://gcc.gnu.org/gcc-6/porting_to.html#overloaded-abs

Strictly, we're trying to take the absolute value of an unsigned integer, which doesn't make sense.

What we're *really* wanting to do is to check whether two unsigned ints are close to each other.

[Alex Valavanis (valavanisalex)]

Also, note that there are some places where we declare the throw(...) behaviour of functions. This kind of declaration is obsolete.

[Alex Valavanis (valavanisalex)]

Fix for the std::abs and throw() issues committed to trunk in r15477

[Stefan Husmann (stefan-husmann)]

I am facing the same problem in the 0.92.x branch.

[Mattia Rizzolo (mapreri)]

somebody wrote a patch to have 0.92.x compile with gcc-7, I linked it here: https://bugs.debian.org/853453#19 - I haven't tested it though.

Maybe that's something that should be fixed for 0.92.x officially too.

[Patrick Storz (ede123)]

Fixed for the 0.92.x branch in
https://gitlab.com/inkscape/inkscape/commit/3876176ec28cac3b70f0b330b760aaa561236ee7

[Qantas94Heavy (qantas94heavy)]

Fix released in Inkscape 0.92.2.