(flex.info)Code-Level And API Options

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16.3 Code-Level And API Options
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'--ansi-definitions, '%option ansi-definitions''
     Deprecated, ignored

'--ansi-prototypes, '%option ansi-prototypes''
     Deprecated, ignored

'--bison-bridge, '%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'.  Note: Bison
     Bridge.

'--bison-locations, '%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'.  Note: Bison Bridge.

'-L, --noline, '%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 Note: Reporting Bugs).

'-R, --reentrant, '%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 Note: 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.

'-+, --c++, '%option c++''
     specifies that you want flex to generate a C++ scanner class.
     Note: Cxx, for details.

'--array, '%option array''
     specifies that you want yytext to be an array instead of a char*

'--pointer, '%option pointer''
     specify that 'yytext' should be a 'char *', not an array.  This
     default is 'char *'.

'-PPREFIX, --prefix=PREFIX, '%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.

'--main, '%option main''
     directs flex to provide a default 'main()' program for the scanner,
     which simply calls 'yylex()'.  This option implies 'noyywrap' (see
     below).

'--nounistd, '%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.  Note:
     option-always-interactive.  Note: option-read.

'--yyclass=NAME, '%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.
     Note: Cxx.