frama-c man page

frama-c[.byte] — a static analyzer for C programs

frama-c-gui[.byte] — the graphical interface of frama-c


frama-c [ options ] files


frama-c is a suite of tools dedicated to the analysis of source code written in C. It gathers several static analysis techniques in a single collaborative framework. This framework can be extended by additional plugins placed in the $FRAMAC_PLUGIN directory. The command

frama-c --plugins

will provide the full list of the plugins that are currently installed.

frama-c-gui is the graphical user interface of frama-c. It features the same options as the command-line version.

frama-c.byte and frama-c-gui.byte are the ocaml bytecode versions of the command-line and graphical user interface respectively.

By default, Frama-C recognizes .c files as C files needing pre-processing and .i files as C files having been already pre-processed. Some plugins may extend the list of recognized files. Pre-processing can be customized through the -cpp-command and -cpp-extra-args options.



Options taking an additional parameter can also be written under the form


This form is mandatory when param starts with a dash ('-').

Most options that take no parameter have a corresponding


option which has the opposite effect.

Help options

gives a short usage notice.
prints the list of options recognized by Frama-C's kernel
-verbose n
Sets verbosity level (default is 1). Setting it to 0 will output less progress messages. This level can also be set on a per-plugin basis, with option -plugin-verbose n. Verbosity level of the kernel can be controlled with option -kernel-verbose n.
-debug n
Sets debugging level (default is 0, meaning no debugging messages). This option has the same per-plugin (and kernel) specializations as -verbose.
Sets verbosity and debugging level to 0.

Options controlling Frama-C's kernel

-absolute-valid-range <min-max>
considers that all numerical addresses in the range min-max are valid. Bounds are parsed as ocaml integer constants. By default, all numerical addresses are considered invalid.
-add-path p1[,p2[...,pn]]
adds directories <p1> through <pn> to the list of directories in which plugins are searched.
merges function definitions modulo renaming. Defaults to no.
allows duplication of small blocks during normalization of tests and loops. Otherwise, normalization uses labels and gotos. Bigger blocks and blocks with non-trivial control flow are never duplicated. Defaults to yes.
reads ACSL annotations. This is the default. Annotations are pre-processed by default. Use -no-pp-annot if you don't want to expand macros in annotations.
-big-ints-hex max
integers larger than max are displayed in hexadecimal (by default, all integers are displayed in decimal)
performs integrity checks on the internal AST (for developers only).
generates contracts for assembly code written according to gcc's extended syntax. Defaults to yes.
automatically marks contracts generated from asm as valid. Defaults to no.
allows implicit cast between the value returned by a function and the lvalue it is assigned to. Otherwise, a temporary variable is used and the cast is made explicit. Defaults to yes.
folds all syntactically constant expressions in the code before analyses. Defaults to no.
variables with const qualifier must be actually constant. Defaults to yes. The opposite option is -unsafe-writable.
When analyzing an annotation, the default behavior (the -no version of this option) when a typechecking error occurs is to reject the source file as is the case for typechecking errors within the C code. With this option on, the typechecker will only output a warning and discard the annotation but typechecking will continue (errors in C code are still fatal, though).
-cpp-command cmd

Uses cmd as the command to pre-process C files. Defaults to the CPP environment variable or to

gcc -C -E -I.

if it is not set. In order to preserve ACSL annotations, the preprocessor must keep comments (the -C option for gcc). %1 and %2 can be used in cmd to denote the original source file and the pre-processed file respectively.

-cpp-extra-args args
Gives additional arguments to the pre-processor. This is only useful when -preprocess-annot is set. Pre-processing annotations is done in two separate pre-processing stages. The first one is a normal pass on the C code which retains macro definitions. These are then used in the second pass during which annotations are pre-processed. args are used only for the first pass, so that arguments that should not be used twice (such as additional include directives or macro definitions) must thus go there instead of -cpp-command.
indicates that the chosen preprocessor accepts the same set of options as GNU cpp. Defaults depends on the installed preprocessor at configure time. See also -pp-annot.
-custom-annot-char c
uses character c for starting ACSL annotations.
When on, load all the dynamic plugins found in the search path (see -print-plugin-path for more information on the default search path). Otherwise, only plugins requested by -load-modules will be loaded. Default behavior is on.
-enums repr
Choose the way the representation of enumerated types is determined. frama-c -enums help gives the list of available options. Default is gcc-enums
-float-digits n
When outputting floating-point numbers, display n digits. Defaults to 12.
Floating point operations flush to zero.
display floats as hexadecimal.
display floats with the standard OCaml routine.
display float intervals as [ lower_bound++width ].
forces right-to-left evaluation order for arguments of function calls. Otherwise the evaluation order is left unspecified, as in the C standard. Defaults to no.
adds -I$FRAMAC_SHARE/libc to the options given to the cpp command. If -cpp-gnu-like is not false, also adds -nostdinc to prevent an inconsistent mix of system and Frama-C header files. Defaults to yes.
-implicit-function-declaration <action>
warns or aborts when a function is called before it has been declared. <action> can be one of ignore, warn, or error. Defaults to warn.
Implicit initialization of locals sets padding bits to 0. If false, padding bits are left uninitialized (defaults to yes).
Do not output a journal of the current session. See -journal-enable.
On by default, dumps a journal of all the actions performed during the current Frama-C session in the form of an ocaml script that can be replayed with -load-script. The name of the script can be set with the -journal-name option.
-journal-name name
Set the name of the journal file (without the .ml extension). Defaults to frama_c_journal.
Tries to preserve comments when pretty-printing the source code (defaults to no).
When -simplify-cfg is set, keeps switch statements. Defaults to no.
See -remove-unused-specified-functions
-kernel-log kind:file
copies log messages from the Frama-C's kernel to file. kind specifies which kinds of messages to be copied (e.g. w for warnings, e for errors, etc.). See -kernel-help for more details. Can also be set on a per-plugin basis, with option -plugin-log.
Indicates that the entry point is called during program execution. This implies in particular that global variables cannot be assumed to have their initial values. The default is -no-lib-entry: the entry point is also the starting point of the program and globals have their initial value.
-load file
loads the (previously saved) state contained in file.
-load-module m1[,m2[...,mn]]
loads the ocaml modules <m1> through <mn>. These modules must be .cmxs files for the native code version of Frama-c and .cmo or.cma files for the bytecode version (see the Dynlink section of the OCaml manual for more information). All modules which are present in the plugin search paths are automatically loaded.
-load-script s1[,s2,[...,sn]]
loads the ocaml scripts <s1> through <sn>. The scripts must be .ml files. They must be compilable relying only on the OCaml standard library and Frama-C's API. If some custom compilation step is needed, compile them outside of Frama-C and use -load-module instead.
-machdep machine
uses machine as the current machine-dependent configuration (size of the various integer types, endiandness, ...). The list of currently supported machines is available through -machdep help option. Default is x86_32
-main f
Sets f as the entry point of the analysis. Defaults to 'main'. By default, it is considered as the starting point of the program under analysis. Use -lib-entry if f is supposed to be called in the middle of an execution.
prints an obfuscated version of the code (where original identifiers are replaced by meaningless ones) and exits. The correspondence table between original and new symbols is kept at the beginning of the result.
-ocode file
redirects pretty-printed code to file instead of standard output.
During the normalization phase, some variables may get renamed when different variables with the same name can co-exist (e.g. a global variable and a formal parameter). When this option is on, a message is printed each time this occurs. Defaults to no.
pre-processes annotations. This is currently only possible when using gcc (or GNU cpp) pre-processor. The default is to pre-process annotations when the default pre-processor is identified as GNU or GNU-like. See also -cpp-gnu-like
pretty-prints the source code as normalized by CIL (defaults to no).
outputs the directory where the Frama-C kernel library is installed.
alias of -print-share-path
outputs the directory where Frama-C searches its plugins (can be overidden by the FRAMAC_PLUGIN variable and the -add-path option)
outputs the directory where Frama-C stores its data (can be overidden by the FRAMAC_SHARE variable)
transforms throw and try/catch statements into normal C functions. Defaults to no, unless the input source language has an exception mechanism.
-remove-projects p1,...,pn
removes the given projects p1,...,pn. @all_but_current removes all projects but the current one.
keeps function prototypes that have an ACSL specification but are not used in the code. This is the default. Functions having the attribute FRAMAC_BUILTIN are always kept.
For multidimensional arrays or arrays that are fields inside structs, assumes that all accesses must be in bound (set by default). The opposite option is -unsafe-arrays.
-save file
Saves Frama-C's state into file after analyses have taken place.
-session s
sets s as the directory in which session files are searched.
the current project becomes the default one (and so future -then sequences are applied on it). Defaults to no.
removes break, continue and switch statements before analyses. Defaults to no.
simplifies trivial loops such as do ... while (0) loops. Defaults to yes.
allows one to compose analyzes: a first run of Frama-C will occur with the options before -then and a second run will be done with the options after -then on the current project from the first run.
like -then, but the second group of actions is executed on the last project created by a program transformer.
-then-on prj
Similar to -then except that the second run is performed in project prj. If no such project exists, Frama-C exits with an error.
like -then-last, but also removes the previous current project.
-time file
appends user time and date in the given file when Frama-C exits.
forces typechecking of the source files. This option is only relevant if no further analysis is requested (as typechecking will implicitly occur before the analysis is launched).
-ulevel n
syntactically unroll loops n times before the analysis. This can be quite costly and some plugins (e.g. the value analysis) provide more efficient ways to perform the same thing. See their respective manuals for more information. This can also be activated on a per-loop basis via the loop pragma unroll <m> directive. A negative value for n will inhibit such pragmas.
ignores UNROLL loop pragmas disabling unrolling.
outputs ACSL formulas with utf8 characters. This is the default. When given the -no-unicode option, Frama-C will use the ASCII version instead. See the ACSL manual for the correspondence.
see -safe-arrays
checks that read/write accesses occurring in an unspecified order (according to the C standard's notion of sequence points) are performed on separate locations. With -no-unspecified-access, assumes that it is always the case (this is the default).
outputs the version string of Frama-C.
-warn-decimal-float <freq>
warns when a floating-point constant cannot be exactly represented (e.g. 0.1). <freq> can be one of noneonce, or all
generates alarms when signed downcasts may exceed the destination range (defaults to no).
generates alarms for signed operations that overflow (defaults to yes).
generates alarms when unsigned downcasts may exceed the destination range (defaults to no).
generates alarms for unsigned operations that overflow (defaults to no).

Plugin-specific options

For each plugin, the command

frama-c -plugin-help

will give the list of options that are specific to the plugin.

Exit Status

Successful execution
Invalid user input
User interruption (kill or equivalent)
Unimplemented feature
4 5 6
Internal error
Unknown error

Exit status greater than 2 can be considered as a bug (or a feature request for the case of exit status 3) and may be reported on Frama-C's BTS (see below).

Environment Variables

It is possible to control the places where Frama-C looks for its files through the following variables.

The directory where kernel's compiled interfaces are installed.
The directory where Frama-C can find standard plugins. If you wish to have plugins in several places, use -add-path instead.
The directory where Frama-C data (e.g. its version of the standard library) is installed.

See Also

Frama-C user manual$FRAMAC_SHARE/manuals/user-manual.pdf

Frama-C homepage: http://frama-c.com

Frama-C BTS: http://bts.frama-c.com

Referenced By

frama-c-gui(1) is an alias of frama-c(1).