On Mon, 2009-01-26 at 21:03 +0200, gleb.alexeev@gmail.com wrote:

Mon Jan 26 20:58:32 EET 2009 gleb.alexeev@gmail.com * Warn if C dependencies not found (kind of fixes #262)

This is just a basic check - generate a sample program and check if it compiles and links with relevant flags. Error messages (warning messages, actually) could use some improvement.

I think this is basically ok. There are some further improvements we will need to make, but we can do that on top of what we've got now so I'm pushing your patch now. It also makes it easier for other people to report how well it works in practise. One is that we'll have to do the check in a slightly different place for packages that use ./configure scripts since the post-conf action is where configure runs and it drops a .buildinfo file. I can do that bit. We can improve the error messages as you suggested. I suspect that we will need to include all the headers and link all the libs in one go, at least in the first go. That is because on many systems, some headers cannot be included without other headers being included first. Similarly static libraries can have dependencies on other static libs, so linking to just one may fail. Of course then the tricky part is if it fails, which header or lib do blame? If we do the compilation and link steps separately then distinguishing the headers from libs is easy. Now for the tricky bit. We do not know the dependencies between the headers or libs, however we do know that they have been listed in dependency order. So if we try all prefixes in sequence then we should eventually hit the one that fails, but in each case where we try a new one we're also using its dependencies. For example if we have: includes: foo.h bar.h baz.h and it so happens that bar.h and baz.g needs foo.h to be included first. So we try: foo.h bar.h baz.h Now if that fails, we try: foo.h foo.h bar.h foo.h bar.h baz.h And at some point one of those will fail and we can report that the extra one is the cause of the problem. So it does mean we cannot report more than one problem accurately, but never mind. So we should generalise the test function to take a list of headers and libs. Duncan