[Flex-help] Why it does not work ?

[Frank Y. <pro...@gm...>]

Hi , all ! Let us study the question.  I have three char buffers A , B and C ;
buffer A: "data1"
buffer B: "data2"
buffer C: "data3"

rule: data1data2data3data4  printf( "\n Experiment is  successful!" );
In order to  find the string "data1data2data3" , I have written the
following code, however, it does not find the string
"data1data2data3". I found yy_state is always one when
yy_switch_to_buffer is run. What should I do ? Please tell me.

Source Code:
%{
	#define  FILE_NUM                       4
  	YY_BUFFER_STATE       Channel[4]  ;
	static unsigned int            BufferIndex ;
	int yywrap(void);
%}

	
%%
data1data2data3data4  printf( "\nExperiment is  successful!" );
<<EOF>> 	{
			BufferIndex++;
			if ( BufferIndex<FILE_NUM )
			{
				
				yy_switch_to_buffer( Channel[BufferIndex] );
			}
			
			else
			{
				yyterminate();
			}
		}
%%

int main( int argc, char* argv[] )
{	
	unsigned int nCounter;
	FILE*        pFile[4];	
	// checking parameter
	if( argc <FILE_NUM+1 )
	{
		printf( "usage: Buffer filename1 filename2....." );
		exit(0);
   	}

 	// open the file
   	for( nCounter=0; nCounter<FILE_NUM; ++nCounter )
   	{
      		pFile[nCounter] = fopen( argv[nCounter+1], "r" );
      		if ( !pFile[nCounter] )
      		{
			printf( "\ncan not open the data%d", nCounter+1 );
			exit(1);
      		}
		// Create Buffer
		Channel[nCounter] = yy_create_buffer(pFile[nCounter], YY_BUF_SIZE);
   	}
	
   	yy_switch_to_buffer( Channel[BufferIndex] );
   	yylex( );

    	system( "pause" ) ;
    	for ( nCounter=0; nCounter<FILE_NUM; ++nCounter )
    	{	
		fclose( pFile[nCounter] );
    	}

   	return 0;
}

int yywrap(void)
{
        return 1;
}