Build failure: 'errno' undeclared. Missing an include?

[Cafuego]

I've started getting build failure reports from my daily autobuild scripts for Lucid, Natty, Maveric, Oneiric and Precise. It looks as util/units.cpp needs errno.h included.

  CXX util/units.o
util/units.cpp: In member function 'bool Inkscape::Util::UnitTable::loadText(const Glib::ustring&)':
util/units.cpp:148: error: 'errno' was not declared in this scope
util/units.cpp:216: error: 'errno' was not declared in this scope
util/units.cpp: In member function 'bool Inkscape::Util::UnitTable::save(const Glib::ustring&)':
util/units.cpp:244: error: 'errno' was not declared in this scope
util/units.cpp:263: error: 'errno' was not declared in this scope
make[4]: *** [util/units.o] Error 1
make[4]: Leaving directory `/build/buildd/inkscape-0.49~devel+10918+6~lucid1/src'
make[3]: *** [all] Error 2
make[3]: Leaving directory `/build/buildd/inkscape-0.49~devel+10918+6~lucid1/src'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory `/build/buildd/inkscape-0.49~devel+10918+6~lucid1'
make[1]: *** [all] Error 2
make[1]: Leaving directory `/build/buildd/inkscape-0.49~devel+10918+6~lucid1'
make: *** [build] Error 2
dpkg-buildpackage: error: debian/rules build gave error exit status 2

Build logs:

https://launchpad.net/~cafuego/+archive/inkscape/+build/3113028/+files/buildlog_ubuntu-lucid-i386.inkscape_0.49~devel%2B10918%2B6~lucid1_FAILEDTOBUILD.txt.gz
https://launchpad.net/~cafuego/+archive/inkscape/+build/3113029/+files/buildlog_ubuntu-maverick-amd64.inkscape_0.49~devel%2B10918%2B6~maverick1_FAILEDTOBUILD.txt.gz
https://launchpad.net/~cafuego/+archive/inkscape/+build/3113043/+files/buildlog_ubuntu-natty-i386.inkscape_0.49~devel%2B10918%2B6~natty1_FAILEDTOBUILD.txt.gz
https://launchpad.net/~cafuego/+archive/inkscape/+build/3113044/+files/buildlog_ubuntu-oneiric-amd64.inkscape_0.49~devel%2B10918%2B6~oneiric1_FAILEDTOBUILD.txt.gz
https://launchpad.net/~cafuego/+archive/inkscape/+build/3113059/+files/buildlog_ubuntu-precise-amd64.inkscape_0.49~devel%2B10918%2B6~precise1_FAILEDTOBUILD.txt.gz

[Alex Valavanis (valavanisalex)]

Yep, Confirmed in lp:inkscape r10918. Error was introduced in r10917, I think.[1] Fix on its way...

[1] http://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/revision/10917

[su_v (suv-lp)]

@Alex - sorry for the change of status, we commented at the same time ;)

[Alex Valavanis (valavanisalex)]

Fixed in lp:inkscape r10919

[su_v (suv-lp)]

@Alex - the other change in r10919 breaks building on Lucid (i.e. with GTK 2.20):
gtk_message_dialog_get_message_area() exists only since gtk 2.22
<http://developer.gnome.org/gtk/2.24/GtkMessageDialog.html#gtk-message-dialog-get-message-area>

Build failure:

  CXX widgets/desktop-widget.o
widgets/desktop-widget.cpp: In member function 'bool SPDesktopWidget::shutdown()':
widgets/desktop-widget.cpp:899: error: 'gtk_message_dialog_get_message_area' was not declared in this scope
make[4]: *** [widgets/desktop-widget.o] Error 1
make[4]: Leaving directory `/build/buildd/inkscape-0.49~devel+10919+6~lucid1/src'
make[3]: *** [all] Error 2
make[3]: Leaving directory `/build/buildd/inkscape-0.49~devel+10919+6~lucid1/src'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory `/build/buildd/inkscape-0.49~devel+10919+6~lucid1'
make[1]: *** [all] Error 2
make[1]: Leaving directory `/build/buildd/inkscape-0.49~devel+10919+6~lucid1'
make: *** [build] Error 2

<https://launchpad.net/~cafuego/+archive/inkscape/+build/3113279>

[Kris (kris-degussem)]

I'm sorry for the issues with cerrno.
I sometimes encounter header includes that are not necessary anymore and so I drop them.
I verified building on windows with btool and it build without an issue ... maybe it is good not to do anything for a while :(

[Alex Valavanis (valavanisalex)]

@~suv: Oops... I didn't mean to commit that other change! Reverted in r10920.

[su_v (suv-lp)]

Kris wrote:
> (…) maybe it is good not to do anything for a while :(

No, that would be an overreaction IMHO ;)
The issue was easily and quickly solved (thx Alex!), and didn't affect _all_ non-windows build platforms (AFAIU it seems to depend on include policies of certain GCC versions and / or system configs - r10917 and later revisions built equally well (without failure) with an older version of GCC on osx).

@Alex - is there a page summarizing such requirements for include files, e.g. for Ubuntu?

[Alex Valavanis (valavanisalex)]

@Kris - I think the code cleanup work is really important... I think most people will happily accept a few easily-corrected build errors in the development trunk as the price of long-term maintainability/stable API compatibility. I've introduced several build errors during my recent GSEAL/Gtk3 hacking, so you're not alone! At worst, it's a case of a bzr revert.

@~suv - I had a very quick check for changes relating to errno.h in the libstdc++ documentation, but couldn't find anything. I guess it's safest to assume that we can't rely on "errno" being defined in any header except for errno.h itself.

[ScislaC (scislac)]

Kris: I just want to add a third comment saying please don't let this deter you. You're fighting the good fight and honestly, I can't think of any developer with the project who didn't at least once break compilation on another platform (it's not uncommon to tell you the truth).

[Cafuego (cafuego)]

Happily building again (on Lucid) as of at least r10915, thanks Alex!

@Kris: Don't stop working just because different build environments make different assumptions. The problem was found and fixed, which is precisely right. Thanks for helping to make Inkscape better :-)

[Cafuego (cafuego)]

Ugh, read my apt line wrong ... working as of r10920.