How do I force a 32-bit build of Boost with GCC?

Question

How do I force a 32-bit build of Boost with GCC? Currently attempting by putting this line in my user-config.jam, but it does not work:

using gcc : 4.1.2 : g++ : compileflags="-m32" ;

Bearce

To build it using bjam, I think you'd do this: bjam address-model=32 architecture=x86 – Wavy

Is this on a Linux system…? I generally cheat by using setarch i686 make or similar. I don't know if that'd work for Boost, particularly, though. (And, in that case, you could just download the 32-bit binary for your OS, so I'm guessing perhaps you're on another system.) – Worsted

Answer 1

If you are using C++ Boost 1.40, use:

bjam address-model=32

If you are using eariler version, consider upgrading. If you cannot, use

bjam address-model=32 architecture=x86

I also recommend that you take a look at the fine manual

Aristocrat

Oh yeah... that "fine manual" is great. I love all the examples they provide. (Sarcasm) – Bearce

Patches are welcome. However, I am not exactly sure that explicitly adding a full command like example for every single property listed at the above URL will do much other than bloating the size of docs. – Aristocrat

Note that if you have a 64 bits version of gcc, you should take a look at @AndrewMeadows answer. – Caoutchouc

Using Boost 1.44 on OS X 10.6.8, I still find it necessary to specify architecture=x86. – Dioscuri

Even for Boost 1.49.0 I had to use the architecture=x86 flag to get this to work on Mac OS X 10.8. – Tawnytawnya

Answer 2

This answer helped me toward a solution that worked for me. I was trying to compile a 32-bits version of boost_1_43_0 on 64-bits debian and eventually came up with this:

./bjam                 \
  cflags=-m32          \
  cxxflags=-m32        \
  address-model=32     \
  threading=multi      \
  architecture=x86     \
  instruction-set=i686 \ 
  stage

Fishbowl

In addition, if you want to change the compiler, you can specify your compiler version via the boost directory's 'project-config.jam' or 'user-config.jam' by making sure that using gcc : : g++-4.4 ; is used (specified 4.4 for compiling Boost with Matlab MEX (32-bit) files on 64-bit linux). – Hound