GENKSYMS(8) Linux Module Support GENKSYMS(8)
genksyms - generate symbol version information
genksyms [-wq] [-dD] [-V] [-k version] [-p string] [output directory]
Genksyms reads (on standard input) the output from "gcc -E source.c" and generates a file
containing version information.
Depending on the output format indicated by the -k option, the output will either be writ-
ten to a .ver file in the named output directory, or to the standard output.
Genksyms normally looks for explicit symbol table definitions in the source file. All
definitions and declarations of typedef, struct, union and enum will be saved for later
expansion. Every global symbol will also be saved, together with pointers that will
enable a full expansion later on.
When a symbol table is found in the source, the symbol will be expanded to its full defi-
nition, where all structs, unions, enums and typedefs will be expanded down to their basic
part, recursively. This final string will then be used as input to a CRC algorithm that
will give an integer that will change as soon as any of the included definitions changes,
for this symbol.
The version information in the kernel normally looks like: symbol_R12345678, where
12345678 is the hexadecimal representation of the CRC.
Output debugging information; repeating this option increases the verbosity. Debug
level 1 generates moderate information about the actions being taken; debug level 2
enables parser recognition output; debug level 3 enables lexical analysis output.
Dump expanded symbol definitions to stderr. For debugging use only.
Display a summary of options and immediately exit.
-k version, --kernel version
Select the version of the kernel for which to generate output. Omitting this
option assumes a version below 2.1.0. Versions below 2.1.18 use checksum version
1, and produce their output in the directory given on the command line. Versions
2.1.18 and above use checksum version 2 and produce their output on stdout.
-p string, --prefix string
Prepend the given string to the CRCs generated for all symbols. This is intended
for use with, e.g., SMP kernels, wherein the modules are not compatible at a level
below that described by the data types. This is primarily caused by inline func-
tion expansions in the module code itself.
Quiet warnings, i.e. reverse the -w option.
Display the version of genksyms.
Enable warnings due to unrecognized syntax and declared but undefined structures.
These warnings are normally suppressed.
The -h option is broken; --help is fine.
genksyms [-V | --version] should display version information and then exit immediately.
Instead, it prints the version information and behaves as if no options were given.
This versioning concept is a result from discussions, not at least on the KERNEL-channel,
with a lot of people.
The genksyms utility was created in 1994 by Bjorn Ekwall <email@example.com> being mostly
inspired by Jacques Gelinas <firstname.lastname@example.org> and Jeremy Fitzhardinge
It was rewritten in 1996 by Richard Henderson to use a proper lexer and parser.
Linux January 30, 2002 GENKSYMS(8)