Building Chez Scheme Version 10.5.0
Copyright 1984-2026 Cisco Systems, Inc.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

  http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.


PREREQUISITES

On Unix variants:

 * Make [where GNU make is needed for some extra things, like docs]
 * GCC, Clang, or a similarly capable compiler
 * Header files and libraries for ncurses   [unless --disable-curses]
 * Header files and libraries for X windows [unless --disable-x11]

On Windows:

 * Microsoft Visual Studio 2026, 2022, 2019, or 2017


GETTING STARTED

This repository contains the source code for Chez Scheme. It includes
the boot and header files in "boot/pb" for the portable bytecode
Chez Scheme machine type, which can be used to build native
machine types. You can also create initial boot files using
an existing Chez Scheme build.

If you're on Windows, see the WINDOWS VIA COMMAND PROMPT section later
in this file. Otherwise, carry on to CONFIGURING AND BUILDING.


CONFIGURING AND BUILDING

Assuming you have boot files, building and installing is the usual
sequence:

  ./configure
  make
  sudo make install

This should not take more than a few minutes, after which the
commands `scheme` and `petite` can be used to run Chez Scheme and
Petite Chez Scheme, while `man scheme` and `man petite` can be used to
view the manual pages. Chez Scheme and Petite Chez Scheme are
terminal-based programs, not GUIs. They both incorporate sophisticated
command-line editing reminiscent of tcsh but with support for
expressions that span multiple lines.

Uninstalling on Unix-like systems is as simple as running:

  sudo make uninstall


WAYS TO GET BOOT FILES

1. The portable boot files are used by default. You can use

     ./configure --pb
     make bootquick XM=<machine type>

   to create boot files for <machine type>. You can use "auto"
   in place of <machine type> to build for an inferred machine
   type.

2. If you have some version of Chez Scheme installed as `scheme`, then

     ./configure --force
     make re.boot

   creates boot files for an inferred <machine type>, or

     ./configure --force -m=<machine type>
     make re.boot

   creates boot files for <machine type>. You can supply
   `SCHEME=<scheme>` to run <scheme> instead of `scheme`. A `make`
   afterward builds for <machine type>.

   If your existing Chez Scheme installation is recent enough, you
   may be able to create boot files more quickly using `cross.boot`
   instead of `re.boot`.

   The `--force` flag disables the requirement to have either existing
   boot files for the target machine or pb boot files for creating
   them.

3. If you plan to build on many different machines and you have a new
   Chez Scheme build for some machine, within that build you can use

     make boot XM=<machine type>

   to quickly create boot files for any <machine type>.


DETAILS

The source code for Chez Scheme comes in three parts:

 * A set of Scheme source files found in the subdirectory "s".
   Compiling these produces the boot files "petite.boot" and
   "scheme.boot", along with two header files, "equates.h" and
   "scheme.h".

 * A set of C source files found in the subdirectory "c". Compiling
   and linking these files produces the executable "scheme" (or
   "scheme.exe" on Windows). Compiling the C sources requires the two
   header files produced by compiling the Scheme source code.

 * A set of portable boot files found in the subdirectory "boot/pb"
   used to bootstrap the compiler.

The "configure" script attempts to determine what type of machine it's
on and looks for boot files for the machine in a "boot" subdirectory
(either in the same directory as the "configure" script or the current
directory if "configure" is run from elsewhere). If it finds suitable
boot files, "configure" creates several files and directories in the
current directory (which does not have to be the same as the source
directory):

 * "Makefile" in the root (top level) directory.

 * "main.zuo" in the root (top level) directory.

 * A workarea as a subdirectory named for the machine type (e.g.,
   "ta6le" for threaded 64-bit linux). The workarea is a mirror of the
   root directory, with subdirectories named "c", "s", and so on.
   Compilation takes place in the workarea.

 * Within the workarea, the files "Mf-config" and "main.zuo".

The "configure" script recognizes various options for controlling the
type of build and the installation location. For example,
`--nothreads` requests a build without support for native threads,
`--32` requests a 32-bit build, and `--installprefix <pathname>`
specifies the installation root. Run `./configure --help` for
information on the supported options.

For platforms without support for native-code compilation in Chez
Scheme, use a machine specification like `-m=tpb64l`, which is a
threaded, 64-bit, little-endian build. The "configure" script will
still attempt to infer compilation and linking flags for the kernel; if
you need to give it a hint, you can use the `--os` flag with something
like `--os=tXle`, which indicates a threaded configuration (due to the
leading "t") on Linux (due to the trailing "le").

The generated makefile mostly just ensures that a `zuo` executable is
built in a `bin` directory, and then it defers the actual build work
to `zuo`, which uses the "main.zuo" file. If you have `zuo` installed,
you can use `zuo` directly instead of `make`: in that case, you may
wish to use `./configure ZUO=<zuo>`. In general, instead of
the command `make X` to build target `X` as described below, you can
use `zuo . X` (or `bin/zuo . X` after `bin/zuo` is built).

The makefile supports several targets:

 * `make` or `make build`

   Compiles and links the C sources to produce the executable, then
   (except for cross builds) bootstraps the Scheme sources.

   Bootstrapping involves using the freshly built scheme executable
   along with initial boot files to compile the Scheme sources. If the
   new boot files are equivalent to the old boot files, the system is
   bootstrapped. Otherwise, the new boot files are used to create a
   newer set, and those are compared. If this succeeds, the system is
   bootstrapped. Otherwise, the make fails --- which should not
   happen, unless the initial boot files are incorrect or become out
   of sync with the sources.

   When you make a modification to the system that causes the C side
   to get out of sync with the Scheme side so that the build fails,
   the simplest approach is to re-bootstrap via `make re.boot`.

 * `make kernel`

   Compiles just the C sources to produce the executable so that
   running can use existing boot files.

 * `make run`

   Runs the build Chez Scheme without installing.

   Alternatively, you can run the executable directly as

     <workarea>/bin/<machine type>/scheme

   If you have configured with `--installabsolute`, running without
   installing requires either `SCHEMEHEAPDIRS` as

     env SCHEMEHEAPDIRS=<workarea>/boot/<machine type> \
         <workarea>/bin/<machine type>/scheme

   or using the `-B` command-line flag:

     <workarea>/bin/<machine type>/scheme \
       -B <workarea>/boot/<machine type>/petite.boot \
       -B <workarea>/boot/<machine type>/scheme.boot

   Note that <workarea> and <machine type> are typically the same.

   If you use `zuo . run`, then additional arguments after `run` are
   passed along as arguments to `scheme`.

 * `sudo make install`

   Installs the built executables, boot files, example files, and
   manual pages. If the `--installprefix` used with "configure" is
   writable by the current user, then `sudo` is not necessary.

   To install to a staging directory instead of the final installation
   path, use the `--temproot=<dir>` argument to the "configure" script
   or supply `DESTDIR=<dir>` as an argument to after `make install`.

 * `sudo make uninstall`

   Uninstalls the executables, boot files, example files, and manual
   pages. As with `make install`, if the `--installprefix` used with
   "configure" is writable by the current user, then `sudo` is not
   necessary.

 * `make test`  (or `zuo . -j <jobs> test`)

   Runs the build plus runs a set of test programs in various
   different ways, e.g., with different compiler options. It can take
   on the order of an hour, depending on the speed of the machine.

   At the end of a complete run, a summary is shown. It should contain
   one line per test configuration, something like this:

     -------- o=0 --------
     -------- o=3 --------
     -------- o=0 cp0=t --------
     -------- o=3 cp0=t --------
     -------- o=0 spi=t p=t --------
     -------- o=3 spi=t p=t --------
     -------- o=0 eval=interpret --------
     -------- o=3 eval=interpret --------
     -------- o=0 cp0=t eval=interpret --------
     -------- o=3 cp0=t eval=interpret --------
     -------- o=0 ehc=t eoc=f --------
     -------- o=3 ehc=t eval=interpret --------

   If there is anything else in the output, something unexpected
   occurred. See "IMPLEMENTATION.md" for more information.

   To run test sets in parallel, use `zuo` instead of `make`, and
   supply the `-j` flag between `.` and `test`.

   There are also `test-one` (a representative test), `test-some` (a
   handful of representative tests), `test-some-fast` (omits
   interpreter tests from `test-some`), and `test-more` (additional
   configurations) targets.

 * `make boot XM=<machine type>` or `make bootquick XM=<machine type>`

   Creates boot files for a supported machine type, which is not
   necessarily the current machine type. The boot files are written to
   a subdirectory in "boot".

   The difference between `boot` and `bootquick` is that the latter
   assumes that up-to-date boot files are in place for the current
   machine type, and it compiles the cross compiler in unsafe mode. So,
   `bootquick` is faster, but `boot` is more helpful during
   development.

   Use "auto" for <machine type> as a shorthand for an inferred
   machine type after configuring with `--pb`.

   When using `zuo`, the `boot` and `bootquick` targets take arguments
   instead of using variables. So, the corresponding commands are
   `zuo . boot <machine-type>` and `zuo . bootquick <machine-type>`.

 * `make cross.boot`

   Creates boot files for the configured machine type using an
   existing `scheme` executable, which must be sufficiently compatible
   version of Chez Scheme. (It doesn't need to be the same version,
   but it needs to have some compatible internal structure.) Supply
   `SCHEME=<scheme>` to select the Scheme implementation.

   To use this target for a machine type whose boot files are not
   present (which would be typical for this target), run "configure"
   with the `--force` flag.

   When using `zuo`, use the `boot` target, but also supply
   `SCHEME=<scheme>` or `--host-scheme <scheme>`, or supply
   `--host-workarea <dir>` to use a Scheme built in existing workarea.
   In that last case, add `hostm=<machine type>` if the workarea's
   machine type does not match the machine type configured here.

 * `make re.boot`

   Like `make cross.boot`, but requires less compatibility from the
   existing Chez Scheme implementation, so it works with much older
   versions of Chez Scheme.

   When using `zuo`, use the `reboot` target with the same options as
   the `boot` target.

 * `make bootfiles`

   Runs the build plus uses the locally built system to recreate the
   boot and header files for multiple machine types --- each machine
   type for which a subdirectory exists in the top-level "boot"
   directory. To include a supported machine type that isn't already
   represented in "boot", simply add the appropriate subdirectory as
   empty or use `make boot XM=<machine type>` first.

 * `make docs`

   Runs the build plus generates HTML and PDF versions of the Chez
   Scheme Users Guide and the release notes. Unlike the other build
   targets, the documentation is not built in the workarea, but rather
   in the "csug" and "release_notes" directories (where "configure" is
   run).

   Building the documentation requires a few prerequisites not required
   to build the rest of Chez Scheme.  The following must be available
   in your PATH:

    * A TeX distribution (including latex, pdflatex, dvips, and gs)

    * ppmtogif and pnmcrop (from Netpbm)

   An X11 installation is not required, but ppmtogif does require an
   "rgb.txt" file, which it will automatically locate in the common
   X11 installation locations. If ppmtogif fails because it cannot
   find an "rgb.txt" file, you can use the `RGBDEF` environment
   variable to specify the path to a file. If your system has an Emacs
   installation, then you can find an "rgb.txt" file in the "etc"
   directory of the emacs installation. If your system has a Vim
   installation, then it might contain an "rgb.txt" in the directory
   identified by the `VIMRUNTIME` environment variable.

 * `make clean`

   Removes all built elements from the workarea, and then removes
   `bin/zuo` (unless configured with `ZUO=<zuo>`).


WINDOWS VIA COMMAND PROMPT

To build on Windows with MSYS2 and MinGW gcc or Clang, follow the same
instructions as for Unix above, but the result will be a native
Windows build. Cygwin as a compilation target is not currently
supported.

To build on Windows with Microsoft Visual Studio, use

  build.bat <machine type>

where <machine type> is one of the following:

 * pb        (portable bytecode, usually for bootstrapping)
 * ta6nt     (64-bit Intel threaded)
 * a6nt      (64-bit Intel non-threaded)
 * tarm64nt  (64-bit ARM threaded)
 * arm64nt   (64-bit ARM non-threaded)
 * ti3nt     (32-bit Intel threaded)
 * i3nt      (32-bit Intel non-threaded)

If you're using Visual Studio 2026, 2022 or 2019, install "Desktop
development with C++" on the "Workloads" tab. The `build.bat` script
will use `c\vs.bat` to find and set up Microsoft Visual Studio
command-line tools automatically for <machine type>; supply `/keepvs`
if you have set up command-line tools already so that `c\vs.bat`
should be skipped.

The generated executables "scheme.exe" and "petite.exe" are in
"<machine type>\bin\<machine type>", and each relies on generated boot
files in "..\boot\<machine type>" relative to the executable. The
executables are dynamically linked against the Microsoft Visual C++
run-time library "vcruntime140.dll". If you distribute the executables
to a different system, be sure to include the redistributable run-time
library.

The `build.bat` script creates and uses an `nmake`-compatible makefile
to build `zuo.exe` as its first step and as its only step if `/config`
is supplied. You can use `zuo` to drive targets described in DETAILS
above, but you must have Microsoft Visual Studio command-line tools set
up already (perhaps using `c/vs.bat`).

By default, `build.bat` not only builds the "scheme.exe" executable,
it also builds DLLs and libraries to support four linking
combinations: Scheme as a DLL versus a static library, and using the C
runtime system as a DLL versus a statically linked C runtime library.

The `build.bat` script accepts some options that can be specified
after <machine type>:

 * `/config` or `/none`

   Configures for a machine type, including creating the
   `nmake`-compatible "Makefile", but does not build.

 * `/kernel`

   Builds just the "scheme.exe" executable without rebuilding boot
   files.

 * `/only`

   Builds just the "scheme.exe" executable and boot files, instead of
   also building DLLs and library variants.

 * `/dll`

   Specifies that "scheme.exe" should use the Scheme kernel compiled
   as a DLL "csv<vers>.dll", which normally should be included in the
   same directory as "scheme.exe". This is the default.

 * `/exe`

   Specifies that "scheme.exe" should statically link the Scheme
   kernel, instead of relying on a separate "csv<vers>.dll".

 * `/MD`

   Specifies that "scheme.exe" (and its DLL, if any) use the
   multi-threaded C runtime as a DLL. This is the default.

 * `/MT`

   Specifies that "scheme.exe" (and its DLL, if any) should statically
   link to the multi-threaded C runtime.

 * `/keepvs`

   Specifies that command-line tools like "cl.exe" are available and
   configured already, so `c\vs.bat` should not be run.

 * `/force`

   Specifies that existing boot files should be used for the target
   machine instead of creating via pb.

 * `/test`
   `/test-one`
   `/test-some-fast`
   `/test-some`
   `/test-more`

   Runs tests (default set and other sets) assuming that "scheme.exe"
   is already built.

To create an installer you will need to use WSL or MSYS2:

  cd wininstall
  make workareas
  make

These commands will create workareas and compile binaries for the
`a6nt`, `i3nt`, `ta6nt`, and `ti3nt` machine types and then include
them in a single Windows installer package "Chez Scheme.exe". The
package also includes example files and the redistributable Microsoft
Visual C++ run-time libraries.

When testing on Windows, the iconv tests in "mats/io.ms" require that
a 32-bit or 64-bit (as appropriate) "iconv.dll", "libiconv.dll", or
"libiconv-2.dll" implementing GNU libiconv be located alongside the
executable or via the `PATH` environment variable. Windows sources for
libiconv can be found at:

  http://gnuwin32.sourceforge.net/packages/libiconv.htm

An alternative implementation that uses the Windows API can be found
at:

  https://github.com/burgerrg/win-iconv/releases

If the DLL is not present, the iconv tests will fail.  No other tests
should be affected.

Unset the `TZ` environment variable before running the tests, because
the Cygwin values are incompatible with the Microsoft C Runtime
Library.


EMSCRIPTEN

To target WebAssembly via Emscripten and `emcc`, use the
`--emscripten` flag:

 ./configure --emscripten

The default machine type is pb, but using the `--threads` and/or
`--pbarch` flags can adjust it to tpb, pb32l, or tpb32l. Boot files
for the machine type must be built already, and the configured
workarea is for building an executable and running output via node
with `make run`. The default workarea name is prefixed with "em-", so
output is written to "em-<machine type>/bin/"<machine type>",
including "scheme.js" and "scheme.html".

Boot files will be included in the result as preloads. Use
`--empetite` to omit the compiler as the "scheme.boot" boot file,
keeping only the runtime system as the "petite.boot" boot file.

To build Emscripten output that runs a specific program, compile the
program as a boot file that sets the `scheme-start` parameter, then
supply that boot file's path to `./configure` using the `--emboot=...`
flag. For example, suppose "demo.ss" contains the following:

 (define (go)
   (let loop ([i 10000000])
     (unless (zero? i)
       (loop (sub1 i)))))

 (scheme-start (lambda ()
                 (time (go))))

To compile this file, you'll need a build that runs on the current
machine for the target machine type, probably like this:

 ./configure --pb
 make
 make run

Using that build, create a boot file "demo.boot":

 (compile-file "demo.ss" "demo.so")
 (make-boot-file "demo.boot" (list "petite") "demo.so")

Finally, configure the Emscripten build to use "demo.boot":

 ./configure --pb --emscripten --emboot=demo.boot
 make


CROSS COMPILING

To compile Chez Scheme for a target platform that is different from
the host platform, supply the `--cross` flag to the "configure" script
while also specifying the target machine type, compiler settings to
build for the target platform, and `CC_FOR_BUILD=<compiler>` to
provide a <compiler> suitable for building `bin/zuo`.

For example, to cross compile for Windows with a typical MinGW
installation, use `--toolprefix=x86_64-w64-mingw32-` to specify tools
that compile and link via MinGW:

 ./configure --cross -m=ta6nt --toolprefix=x86_64-w64-mingw32- CC_FOR_BUILD=cc
 make

The configure arguments that are needed to cross compile will vary
with the host and target machines. On a platform where ta6osx is the
native machine type, for example, cross compiling for tarm64osx may be
as simple as specifying an `-arch` flag for the C compiler:

 ./configure --cross -m=tarm64osx CFLAGS="-arch arm64" CC_FOR_BUILD=cc
 make

To cross compile for iOS, provide an iOS SDK path and define the
`TARGET_OS_IPHONE` and `DISABLE_CURSES` macros:

 ./configure \
   --cross \
   -m=tarm64ios \
   CFLAGS="-arch arm64 -isysroot $(xcrun -sdk iphoneos --show-sdk-path) -DTARGET_OS_IPHONE=1 -DDISABLE_CURSES" \
   LDFLAGS="-liconv" \
   CC_FOR_BUILD=clang
 make

When additional configuration is needed for a *host* build (that is,
when just `./configure --pb` would not be enough to build for the host
platform), then more steps are needed. In that case, first build for
the host platform, configuring as needed. Use the result to create
boot files for the target using `make bootquick XM=<target machine>`
(see also the WAYS TO GET BOOT FILES section above). Finally, use both
`--cross` and `--force` to configure for the target platform.

 ./configure -m=ta6osx         # configure for host
 make                          # build for host
 make bootquick XM=tarm64osx   # use host to build target boot files
 ./configure --cross --force -m=tarm64osx CFLAGS="-arch arm64" CC_FOR_BUILD=cc
 make                          # build for target

After `make` to build, use `make install` to gather cross-compiled
components. Typically, `--temproot=<dir>` should be supplied as a
configure argument along with `--cross`, in which case the
installation is placed in a <dir> to be moved to the target platform.
Alternatively, a destination directory can be selected at the installation
step via `DESTDIR`:

 make install DESTDIR=/tmp/staging


CROSS COMPILING SCHEME PROGRAMS

After getting a non-cross build to work on the host platform, using

  make bootquick XM=<machine type>

or

  zuo . bootquick <machine type>

creates a "boot" subdirectory for <machine type> containing boot files
and in the process creates a cross-compilation patch file as
"xc-<machine type>/s/xpatch". Loading that "xpatch" file into Chez
Scheme for the current platform changes functions like `compile-file`
and `make-boot-file` to generate code for the target <machine type>.