DOKK / manpages / debian 12 / flex / flex++.1.en

Programming

NAME

flex - the fast lexical analyser generator

SYNOPSIS

flex [OPTIONS] [FILE]...

DESCRIPTION

Generates programs that perform pattern-matching on text.

Table Compression:

-Ca, --align: trade off larger tables for better memory alignment
-Ce, --ecs: construct equivalence classes
-Cf: do not compress tables; use -f representation
-CF: do not compress tables; use -F representation
-Cm, --meta-ecs: construct meta-equivalence classes
-Cr, --read: use read() instead of stdio for scanner input
-f, --full: generate fast, large scanner. Same as -Cfr
-F, --fast: use alternate table representation. Same as -CFr
-Cem: default compression (same as --ecs --meta-ecs)

Debugging:

-d, --debug: enable debug mode in scanner
-b, --backup: write backing-up information to lex.backup
-p, --perf-report: write performance report to stderr
-s, --nodefault: suppress default rule to ECHO unmatched text
-T, --trace: flex should run in trace mode
-w, --nowarn: do not generate warnings
-v, --verbose: write summary of scanner statistics to stdout
--hex: use hexadecimal numbers instead of octal in debug outputs

FILES

-o, --outfile=FILE: specify output filename
-S, --skel=FILE: specify skeleton file
-t, --stdout: write scanner on stdout instead of lex.yy.c
--yyclass=NAME: name of C++ class
--header-file=FILE: create a C header file in addition to the scanner

--tables-file[=FILE] write tables to FILE

--backup-file=FILE: write backing-up information to FILE

Scanner behavior:

-7, --7bit: generate 7-bit scanner
-8, --8bit: generate 8-bit scanner
-B, --batch: generate batch scanner (opposite of -I)
-i, --case-insensitive: ignore case in patterns
-l, --lex-compat: maximal compatibility with original lex
-X, --posix-compat: maximal compatibility with POSIX lex
-I, --interactive: generate interactive scanner (opposite of -B)
--yylineno: track line count in yylineno

Generated code:

-+, --c++: generate C++ scanner class
-Dmacro[=defn]: #define macro defn (default defn is '1')
-L, --noline: suppress #line directives in scanner
-P, --prefix=STRING: use STRING as prefix instead of "yy"
-R, --reentrant: generate a reentrant C scanner
--bison-bridge: scanner for bison pure parser.
--bison-locations: include yylloc support.
--stdinit: initialize yyin/yyout to stdin/stdout
--nounistd: do not include <unistd.h>
--noFUNCTION: do not generate a particular FUNCTION

Miscellaneous:

-c: do-nothing POSIX option
-n: do-nothing POSIX option

-?

-h, --help: produce this help message
-V, --version: report flex version

SEE ALSO

The full documentation for flex is maintained as a Texinfo manual. If the info and flex programs are properly installed at your site, the command

: info flex

should give you access to the complete manual.

May 2023

The Flex Project