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CRANGLER(1) User Commands CRANGLER(1)


crangler - C source transformation


crangler [-?] [-h] [--help]

crangler file.json


crangler is a command-line utility that makes changes to a preprocessed C file that are prescribed in a JSON configuration file.

The supported transformations are:

Add a contract (pre/post/assigns) to a named C function.
Add a loop contract to a loop identified by the name of the function containing the loop and a loop number.
Remove the static storage classifier from a function or a variable.
Replace a function call by a call to a stub.

The resulting source file is written to standard output or to a file specified in the JSON configuration.


The following JSON configuration file makes crangler preprocess remove_static1.c. While processing this file to produce a preprocessed result, no non-standard include paths or defines reqired. Transformations configured here are removing the static storage classifier from all functions matching the regular expression foobar[12], and replacing calls to bar by calls to a function called bar_stub. No objects are listed that require transformation. The result is written to standard output.


"sources": [
"includes": [],
"defines": [],
"functions": [
"foobar[12]": [
"remove static"
"bar": [
"stub bar_stub"
"objects": [],
"output": "stdout" }


All tools honor the TMPDIR environment variable when generating temporary files and directories.


If you encounter a problem please create an issue at


2021, Daniel Kroening

June 2022 crangler-5.59.0