Bo Peng wrote: > On 7/5/06, Jean-Marc Lasgouttes <[EMAIL PROTECTED]> > wrote: >> What happens when a file from local boost is changed? This happens >> from time to time (small tweaks to allow newer gcc or odd system). > > Scons will not know that so a manual full rebuild is required (remove > build directory and rebuild). I am not sure if autotools can detect > such changes and do a rebuild automatically.
It can. > You see, scons tries to guarantee a correct incremental build, by > building a dependency tree each time. (My understanding is that > autotools do not do this well so although make starts faster, > incremental rebuild may fail.) autotools do that well. It is slow, but it is correct. The only cases where I needed to rerun autogen.sh and configure manually where some larger reorganizations involving renamed and new files. > By moving boost out of reach of scons, > I reduce start time significant, at a cost of potential incorrect > incremental rebuild. I may, however, include boost to the dependency > tree if fast_start=no. > > Everything comes at a cost. :-) Yes, but if scons removes parts from the dependency tree because of speed then this makes it unsuable for developer use. IIRC autotools have the option to turn dependencies off completely. This is useful for people who just do one build. IMHO something like this (I guess that fast_start=yes is similar) would also be useful for scons, but the default should be to calculate all dependencies. Georg
