Working on a socketbased scanner (continuous stream) using Flex for pattern recognition. Flex doesn't find a match that overlaps 'array bounderies'. So I implemented yywrap() to setup new array content as soon yylex() detects <> (it will call yywrap). No success so far.

Basically (for pin-pointing my problem) this is my code:

%{

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define BUFFERSIZE 26
                     /*   0123456789012345678901234 */
char cbuf1[BUFFERSIZE] = "Hello everybody, lex is su";  // Warning, no '\0'
char cbuf2[BUFFERSIZE] = "per cool. Thanks!         ";
char recvBuffer[BUFFERSIZE];

int packetCnt = 0;

YY_BUFFER_STATE bufferState1, bufferState2;

%}

%option nounput
%option noinput

%%

"super"                 { ECHO; }
.                       { printf( "%c", yytext[0] );}

%%

int yywrap()
{

  int retval = 1;   

  printf(">> yywrap()\n");

  if( packetCnt <= 0 )    // Stop after 2
  {
    // Copy cbuf2 into recvBuffer
    memcpy(recvBuffer, cbuf2, BUFFERSIZE);

    //
    yyrestart(NULL); // ?? has no effect

    // Feed new data to flex
    bufferState2 = yy_scan_bytes(recvBuffer, BUFFERSIZE); 

    //
    packetCnt++;

    // Tell flex to resume scanning
    retval = 0;   
  }

  return(retval); 
}

int main(void)
{
  printf("Lenght: %d\n", (int)sizeof(recvBuffer)) ;

  // Copy cbuf1 into recvBuffer
  memcpy(recvBuffer, cbuf1, BUFFERSIZE);

  //
  packetCnt = 0;

  //
  bufferState1 = yy_scan_bytes(recvBuffer, BUFFERSIZE);

  //
  yylex();

  yy_delete_buffer(bufferState1);
  yy_delete_buffer(bufferState2);

  return 0;
}

This is my output:

dkmbpro:test dkroeske$ ./text 
Lenght: 26
Hello everybody, lex is su>> yywrap()
per cool. Thanks!         >> yywrap()

So no match on 'super'. According to the doc the lexxer is not 'reset' between yywrap's. What do I miss? Thanks.