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cjit(1) - Just-In-Time interpreter for C ​

CJIT, January 2025

Synopsis ​

text
cjit [options] <files> [-- app arguments]
  • [options] are prefixed by single or double dash and may require an argument.
  • <files> can be one or more paths to any source (.c), object (.o) or libraries (.dll, .dylib, .so).
  • [-- app arguments] means all arguments following a double dash are passed as-is to the running application.

Description ​

CJIT is a lightweight C interpreter that lets you run C code instantly, without needing to build it first. In addition to just-in-time execution, it can do everything a C compiler does, including call functions from any installed library, and generate executables. It is also designed to be a drop-in replacement for gcc(1) and clang(1), for instance using CC=cjit as an environment setting.

Options ​

  • -h
    Displays a summary of the command-line options available with cjit. It is useful for users who need a quick reference on how to use the tool. This manual is meant to complete that knowledge with more in-depth information.

  • -v
    Prints the version number of cjit. It is helpful for verifying the specific version you are working with, especially when troubleshooting or reporting issues: always include the version output. It can also be quickly added to any command line combination to show the internal state of cjit, for instance include and library paths configured, cflags, and linked libraries.

  • -q
    Suppresses all non-essential output, providing a quieter operation. Only critical errors are displayed. This option is turned on by default when CJIT is launched inside a script (no tty).

  • -C <...flags...>
    Use this option to specify custom flags for the interpreter or compiler. If not set, cjit uses the flags defined in the environment variable CFLAGS.

  • -c
    Only compiles a single provided source file, without executing it, to produce an object file. This option will generate a new pre-compiled object file named like the given source, changing its extension from .c to .o, unless a new name is specified using -o.

  • -o <filename>
    Specifies an output filename. When included on the command line it switches CJIT to build mode and compiles all the source files into an executable but does not run the resulting program. You must provide the path for the output executable.

  • -D key[=value]
    Defines a macro key, and optionally its value, for the preprocessor, just like a #define directive included inside the source. You can specify a simple symbol or use key=value to define a macro with a specific value.

  • -I <path>
    Adds a directory path to the list of paths searched for header files. This is particularly useful if your project includes headers that are not in the standard system directories. For more information see the paths section.

  • -l <name>
    Links a specific shared library. On Windows the name is that of a DLL file without its extension. On UNIX systems, including GNU/Linux and BSD, provide the library name without the lib prefix, for example use -lssl for libssl.so.

  • -L <path>
    Adds a directory path to the library search paths. This is helpful when your project depends on libraries that are located in non-standard directories. For more information see the paths section.

  • -e <function>
    Specifies a different entry function than the default main function. It is useful if your program has multiple potential entry points, or if you want to try a different one at your own risk.

  • -p <path>
    Writes the process ID of the executing program to the specified file. This is useful for managing and monitoring the running process.

  • --verb
    Enables verbose logging, which provides more detailed information about the actions CJIT is performing. It is useful for debugging and understanding the compilation and execution process.

  • --xass [path]
    Extracts runtime assets required by CJIT to run your program. If a path is specified, the assets are extracted to that location; otherwise, they are extracted to the default directory, which is located in AppData\Local\Temp\CJIT-vN.N.N on Windows and in /tmp/cjit-vN.N.N on POSIX systems.

  • --xtgz <path>
    Extracts all files from a specified USTAR format tar.gz archive. This is useful for setting up project dependencies or resources packaged in an archive. For instance it is used to set up the cjit-demo.tar.gz tutorial assets by the script found at https://dyne.org/cjit/demo.

Author ​

This manual is Copyright (c) 2025 by the Dyne.org foundation.

Written by Denis Roio https://jaromil.dyne.org.

Licensing ​

CJIT is licensed under the GNU General Public License version 3 (GPLv3) or any later version published by the Free Software Foundation.

The GPLv3 grants you four freedoms:

  • Use: you may use this software for any purpose.
  • Study and modify: you may study how CJIT works, and modify it to make it do what you wish.
  • Distribute: you may redistribute copies of CJIT so that others can benefit from it.
  • Distribute modified versions: you may distribute your modifications if you grant others the same freedom.

This is a human-readable summary and not a substitute for the license. For the full text of the GPLv3 visit https://www.gnu.org/licenses/gpl-3.0.html. Components included in CJIT are copyrighted and licensed by their respective vendors, and all are compatible with the GPLv3. A list of component licenses is provided in CJIT's source code inside the LICENSES/ folder and detailed by the REUSE.toml file.

This manpage is licensed under the Creative Commons Attribution-ShareAlike 4.0 International License (CC BY-SA 4.0) or any later version. To view a copy of this license, visit http://creativecommons.org/licenses/by-sa/4.0/.

Availability ​

The most recent version of CJIT source code and up-to-date documentation is made available from its website at https://dyne.org/cjit.

See Also ​

tcc(1)