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/*

 *      file I/O version of forward ref handler

 */

#define FILEMODE 0644 /* file creat mode */

#define UPDATE  2 /* file open mode */

#define ABS  0 /* absolute seek */

int Forward =0;  /* temp file's file descriptor */

char Fwd_name[] = { "Fwd_refs" } ;

/*

 *      fwdinit --- initialize forward ref file

 */

fwdinit()

{

 Forward = open(Fwd_name,O_CREAT | O_TRUNC | O_WRONLY, FILEMODE); //creat(Fwd_name,FILEMODE);

 if(Forward <0)

  fatal("Can't create temp file");

 close(Forward); /* close and reopen for reads and writes */

 Forward = open(Fwd_name,UPDATE);

 if(Forward <0)

  fatal("Forward ref file has gone.");

}

/*

 *      fwdreinit --- reinitialize forward ref file

 */

fwdreinit()

{

 F_ref   = 0;

 Ffn     = 0;

 lseek(Forward,0L,ABS);   /* rewind forward refs */

 read(Forward,&Ffn,sizeof(Ffn));

 read(Forward,&F_ref,sizeof(F_ref)); /* read first forward ref into mem */

#ifdef DEBUG

 printf("First fwd ref: %d,%d\n",Ffn,F_ref);

#endif

}

/*

 *      fwdmark --- mark current file/line as containing a forward ref

 */

fwdmark()

{

 write(Forward,&Cfn,sizeof(Cfn));

 write(Forward,&Line_num,sizeof(Line_num));

}

/*

 *      fwdnext --- get next forward ref

 */

fwdnext()

{

 int stat;

 stat = read(Forward,&Ffn,sizeof(Ffn));

#ifdef DEBUG

 printf("Ffn stat=%d ",stat);

#endif

 stat = read(Forward,&F_ref,sizeof(F_ref));

#ifdef DEBUG

 printf("F_ref stat=%d  ",stat);

#endif

 if( stat < 2 ){

  F_ref=0;Ffn=0;

  }

#ifdef DEBUG

 printf("Next Fwd ref: %d,%d\n",Ffn,F_ref);

#endif

}

/*

 *  fwd_done --- closes & deletes forward reference file

 */

fwd_done()

{

        int stat;

        stat = close(Forward); /* Have to close first on MS-DOS or you leave lost clusters. */

#ifndef DEBUG

        if( stat == 0 )        /* If close was successful, delete file */

                unlink(Fwd_name);

#endif

}