19.3 Reentrant Example

First, an example of a reentrant scanner:

         /* This scanner prints "//" comments. */
     
         %option reentrant stack noyywrap
         %x COMMENT
     
         %%
     
         "//"                 yy_push_state( COMMENT, yyscanner);
         .|\n
     
         <COMMENT>\n          yy_pop_state( yyscanner );
         <COMMENT>[^\n]+      fprintf( yyout, "%s\n", yytext);
     
         %%
     
         int main ( int argc, char * argv[] )
         {
             yyscan_t scanner;
     
             yylex_init ( &scanner );
             yylex ( scanner );
             yylex_destroy ( scanner );
         return 0;
        }