Configure script options

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The configure script, which was generated by the autoconf tool, accepts command line options that control various features. It is highly recommended to use the --enable-single-host option to improve the execution speed and compactness of the executables:

./configure --enable-single-host

This option is not used by default because compilation is much longer and requires much more RAM. In fact some platforms may not have enough resources to build the system this way. With --enable-single-host the build takes roughly 500 megabytes and 20 minutes on a 1.2 GHz Athlon Linux machine with the GCC 3.1 compiler instead of 100 megabytes and 2 minutes when --enable-single-host is not used. However, the speed of the Gambit-C interpreter improves by a factor of 2 as a result.

It is also highly recommended to use the GCC compiler to build the system as the source code can take advantage of some GCC extensions. Notably the use of GCC's computed gotos reduces the execution time by roughly 35%.

We recommend that users build Gambit-C with GCC 3.1 or later; GCC 3.1 will compile C code generated by the Gambit-C compiler faster than previous versions of GCC, and will generally produce faster code than previous versions of GCC. For example, the interpreter is about 5% faster than when it is compiled with GCC 2.95.3.

We also recommend that users avoid versions 4.2.* to 4.4.* of GCC, as these versions of GCC require an unreasonable amount of memory to compile the C output of the Gambit compiler for relatively large Scheme programs when Gambit is configured with the --enable-single-host option. For example, with GCC 4.2.4, one cannot compile the "compiler" benchmark in "r6rs" mode in 20GB of memory on x86-64. (GCC version 4.1.2 compiles this program in at most 1.5GB of RAM.) Note that some Linux releases ship with GCC 4.[234].* as the default system compiler, so you might need to build gcc-4.1.2 yourself if you're serious about compiling relatively large Scheme programs.

Other options of the configure script

The detailed list of options accepted by the "configure" script can be obtained with:

./configure --help

Most options are the same as for other autoconf generated configure scripts. For example, you can select the installation directory with the option --prefix:

./configure --prefix=/u/feeley/my-gambit
make install
~/my-gambit/bin/gsi

If the --prefix option is not used, the default is to install all files in /usr/local/Gambit-C and its subdirectories.

The configure options which are specific to the Gambit-C system are:

 --enable-single-host    compile each Scheme module as a single C function
 --enable-cplusplus      compile using C++ compiler
 --enable-guide          include the Gambit Universal IDE (currently broken)
 --enable-shared         build the Scheme runtime system as a shared library
 --enable-debug          build system so that it can be debugged
 --enable-profile        build system so that it can be profiled

The option --enable-cplusplus should be used when applications developed with the Gambit-C compiler are to be linked with code or libraries written in C++. This will compile all of the Gambit-C source code with a C++ compiler instead of a C compiler (this is possible because the code generated by the Gambit-C compiler conforms both to C and C++).

The option --enable-guide will include the Gambit Universal IDE in the Gambit-C runtime system. The option --enable-cplusplus must be used when the option --enable-guide is used. The Gambit Universal IDE requires the Qt GUI library version 3.3. To include GUIDE it is necessary to first build the system without including GUIDE (to have a working Gambit-C compiler) and then rebuild the system with GUIDE enabled. For instance:

./configure --enable-cplusplus
make
make clean
./configure --enable-cplusplus --enable-guide
make

The option --enable-shared will build a shared library for the Gambit-C runtime system. This is not supported on all platforms.

The option --enable-debug and --enable-profile are useful for debugging the system.

By default the configure script will use the GCC compiler to build the system, if it is available. To override this choice or to use special C compiler flags it is possible to set the environment variables CC, CFLAGS, LDFLAGS, etc in the shell or on the configure command line. Object file compilation options should go in CFLAGS, link options should go in LDFLAGS, and options that apply to both can be next to the name of the C compiler in CC. Here are some examples.

  • To use cc instead of gcc:
./configure CC=cc
  • On a Sun Sparc workstation, the following will use the Sun Workshop C/C++ compiler and generate 64 bit executables (the heap can grow beyond 4 Gbytes):
./configure CC="cc -xtarget=native -xarch=v9"
  • On a Compaq Alpha workstation, the following will use the Compaq Tru64 UNIX C/C++ compiler and generate executables that use 32 bit addressing instead of the normal 64 bit addressing (the heap and code will be in the lower 4 GBytes of the address space):
% ./configure CC=cc CFLAGS="-w -D___USE_32_BIT_ADDR" LDFLAGS=-taso
  • By default, Gambit-C's runtime system does not restrict the size of the Scheme heap. A heap overflow will only be signalled when virtual memory is all used up, which can take a long time and cause lots of paging. This is not ideal for an educational environment where endless recursions are commonplace. The symbol ___FORCE_MAX_HEAP can be defined to put a limit on the size of the heap. To get a 5000 kilobyte limit (a reasonable amount for an educational environment) the system could be configured with:
% ./configure CFLAGS="-D___FORCE_MAX_HEAP=5000"
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