Re: [boost] Boost.Threads, the Boost.Build system and GCC

From: John Maddock (John_Maddock_at_[hidden])
Date: 2001-06-10 05:22:52

>Anyway, it would be trivial to add a user flags variable to the
command-lines of all toolset descriptions. I wouldn't mind doing it, but I
worry that it would effectively discourage people from writing a
corresponding feature (which is quite trivial to do, really) and the system
would degenerate into a pile of separate build scripts for different
compilers. Will people use this mechanism simply because they know their
compiler's command-line options and can't be bothered to learn to use the
build system?
<

Ideally we would have a jam feature for all "portable" features (optimise
for space, optimise for speed, pedantic, debug etc), and for all features
that break binary compatabitity.  However there are so many frankly rather
suble features in some compilers (which may change with compiler version
remember) that duplicating these in jam seems like overkill.  It can be
hard enough to figure out what compiler options to use without then having
to go figure out the build systems equivalents as well.

Takings sun's compiler as an example, there are 18 options that effect code
optimisation, only one effects binary compatiblity (-xarch), and some have
multiple settings (-xcache, -xo, -xchip, -xregs, -xunroll).  Add to that 8
floating point options, and 22 library options, again almost all binary
compatible, and I hope you can see my point :-)

- John Maddock
http://ourworld.compuserve.com/homepages/john_maddock/