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%option ansi-definitions
’Deprecated, ignored
%option ansi-prototypes
’Deprecated, ignored
%option bison-bridge
’instructs flex to generate a C scanner that is
meant to be called by a
GNU bison
parser. The scanner has minor API changes for
bison
compatibility. In particular, the declaration of
yylex
is modified to take an additional parameter,
yylval
.
See Bison Bridge.
%option bison-locations
’instruct flex that
GNU bison
%locations
are being used.
This means yylex
will be passed
an additional parameter, yylloc
. This option
implies %option bison-bridge
.
See Bison Bridge.
%option noline
’instructs
flex
not to generate
#line
directives. Without this option,
flex
peppers the generated scanner
with #line
directives so error messages in the actions will be correctly
located with respect to either the original
flex
input file (if the errors are due to code in the input file), or
lex.yy.c
(if the errors are
flex
’s
fault – you should report these sorts of errors to the email address
given in Reporting Bugs).
%option reentrant
’instructs flex to generate a reentrant C scanner. The generated scanner
may safely be used in a multi-threaded environment. The API for a
reentrant scanner is different than for a non-reentrant scanner
see Reentrant). Because of the API difference between
reentrant and non-reentrant flex
scanners, non-reentrant flex
code must be modified before it is suitable for use with this option.
This option is not compatible with the ‘--c++’ option.
The option ‘--reentrant’ does not affect the performance of the scanner.
%option c++
’specifies that you want flex to generate a C++ scanner class. See Cxx, for details.
%option array
’specifies that you want yytext to be an array instead of a char*
%option pointer
’specify that yytext
should be a char *
, not an array.
This default is char *
.
%option prefix="PREFIX"
’changes the default ‘yy’ prefix used by flex
for all
globally-visible variable and function names to instead be
‘PREFIX’. For example, ‘--prefix=foo’ changes the name of
yytext
to footext
. It also changes the name of the default
output file from lex.yy.c to lex.foo.c. Here is a partial
list of the names affected:
yy_create_buffer yy_delete_buffer yy_flex_debug yy_init_buffer yy_flush_buffer yy_load_buffer_state yy_switch_to_buffer yyin yyleng yylex yylineno yyout yyrestart yytext yywrap yyalloc yyrealloc yyfree
(If you are using a C++ scanner, then only yywrap
and
yyFlexLexer
are affected.) Within your scanner itself, you can
still refer to the global variables and functions using either version
of their name; but externally, they have the modified name.
This option lets you easily link together multiple
flex
programs into the same executable. Note, though, that using this
option also renames
yywrap()
,
so you now
must
either
provide your own (appropriately-named) version of the routine for your
scanner, or use
%option noyywrap
,
as linking with
‘-lfl’
no longer provides one for you by default.
%option main
’directs flex to provide a default main()
program for the
scanner, which simply calls yylex()
. This option implies
noyywrap
(see below).
%option nounistd
’suppresses inclusion of the non-ANSI header file unistd.h. This option
is meant to target environments in which unistd.h does not exist. Be aware
that certain options may cause flex to generate code that relies on functions
normally found in unistd.h, (e.g. isatty()
, read()
.)
If you wish to use these functions, you will have to inform your compiler where
to find them.
See option-always-interactive. See option-read.
%option yyclass="NAME"
’only applies when generating a C++ scanner (the ‘--c++’ option). It
informs flex
that you have derived NAME
as a subclass of
yyFlexLexer
, so flex
will place your actions in the member
function foo::yylex()
instead of yyFlexLexer::yylex()
. It
also generates a yyFlexLexer::yylex()
member function that emits
a run-time error (by invoking yyFlexLexer::LexerError())
if
called. See Cxx.
Next: Options for Scanner Speed and Size, Previous: Options Affecting Scanner Behavior, Up: Scanner Options [Contents][Index]