I'm sure this is a faq: please point me to it! I have been looking at the autoconf and automake manuals and on the Internet but have been unable to find out if I can use automake/autoconf to do this. I've also searched on Google without success. I have a source tree which is built using automake[1]. The application is large and being written in C++ and when built the tree ocupies over 1GB. I therefore want to separate the source tree from the build tree in a similar way that FreeBSD uses /usr/src and /usr/obj when building the whole operating system[2]. I'm not entirely sure if this question is more appropriate for the automake list. I've seen that there is a top_builddir and also an ac_top_builddir autoconf macro/variable but am not sure how or what to set to enable me to define this. Ideally I would like to set top_buildir=$top_srcdir/../obj or similar and have this definition propogate down automatically in the subdirectories in my source tree. If anyone can point me to how to do this I would be most obliged. [1][2] The source and object tree structure I am looking to achieve is: src obj src/lib obj/lib src/lib/lib1 obj/lib1 src/lib/lib2 obj/lib2 src/app1 obj/app1 src/app1/sub1 obj/app1/sub1 src/app1/sub2 obj/app1/sub2 src/app2 obj/app2 src/app3 obj/app3 ... ... Regards, Simon Mudd