Hi David, I should have specify the context ...
..for example, in the case you change the SHA1 associated with your external project. If update is disabled, doing a full rebuild will take longer than simply doing an update + incremental build. Especially if other projects depend on the fully rebuild project. With CMake 2.8.8 and lower, wihtin Slicer we had to disable the UPDATE command since it wasn't working reliably. By requiring CMake 2.8.9, things seems to work better on all platform. See [1], [2] and [3] Thanks Jc [1] http://viewvc.slicer.org/viewvc.cgi/Slicer4?view=revision&revision=20615 [2] http://cmake.org/gitweb?p=cmake.git;a=blobdiff;f=Modules/ExternalProject.cmake;h=1997572196997614f152bc7da886beffb85f01ab;hp=301d1fc4d50d850d5abe219eab3a230d55769910;hb=987c017f6b1b49ab832c244166e30e07260432da;hpb=8bb46ee787828c75b825d72b7121296d91bef7d6 [3] http://cmake.org/gitweb?p=cmake.git;a=commit;h=99f6055fe4f047 On Tue, Sep 17, 2013 at 6:06 PM, David Cole <dlrd...@aol.com> wrote: > Some background about the Slicer build system that inspired >> the NamicExternalProjects system discussed by Kent ... >> >> Before CMake 2.8.8, we disabled the UPDATE of external project >> because it was not working well with Visual Studio. While this was >> working as expected, the overall build time was also increased >> because it wasn't doing an incremental rebuild. >> > > The build time increased compared to what? > > A second build, in a no update situation, should yield "no work to do" > because nothing got updated. > > > > As of today, we re-enabled the UPDATE part of external project >> and also require CMake >= 2.8.9 and it works quite well. The >> overall build time is largely decreased. >> > > Again, I don't understand how updating as part of the superbuild could > ever result in a decreased build time... > > > What am I missing here? > D > > -- +1 919 869 8849
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