From @nwc10

I think the answer is "yes unless it encounters __DATA__ or __END__ in that
package, in which case it keeps the FILE* open, attaching it to the package's
DATA filehandle."

See

  case KEY___DATA__​:
  case KEY___END__​: {
  GV *gv;

  /*SUPPRESS 560*/
  if (PL_rsfp && (!PL_in_eval || PL_tokenbuf[2] == 'D')) {
  char *pname = "main";
  if (PL_tokenbuf[2] == 'D')
  pname = HvNAME(PL_curstash ? PL_curstash : PL_defstash);
  gv = gv_fetchpv(form("%s​::DATA", pname), TRUE, SVt_PVIO);
  GvMULTI_on(gv);
  if (!GvIO(gv))
  GvIOp(gv) = newIO();
  IoIFP(GvIOp(gv)) = PL_rsfp;
#if defined(HAS_FCNTL) && defined(F_SETFD)
  {
  int fd = PerlIO_fileno(PL_rsfp);
  fcntl(fd,F_SETFD,fd >= 3);
  }
#endif
  /* Mark this internal pseudo-handle as clean */
  IoFLAGS(GvIOp(gv)) |= IOf_UNTAINT;
  if (PL_preprocess)
  IoTYPE(GvIOp(gv)) = '|';
  else if ((PerlIO*)PL_rsfp == PerlIO_stdin())
  IoTYPE(GvIOp(gv)) = '-';
  else
  IoTYPE(GvIOp(gv)) = '<';
  PL_rsfp = Nullfp;
  }
  goto fake_eof;
  }

in toke.c

note how it copies PL_rsfp into the IoIFP, then sets PL_rsfp = Nullfp before
going to fake_eof, which does fclose on PL_rsfp.

Nicholas Clark

From @gbarr

case KEY\_\_\_DATA\_\_​:
case KEY\_\_\_END\_\_​: \{

Ouch!!!

I always thought you only got the DATA filehandle if you had __DATA__

This means that all the modules that put pod at the end after a __END__
or use AutoLoader are using a filehandle. I can now see how it is
very easy to run out of filehandles.

perl5.005_58 $ find lib -name \*.pm | wc -l
187
perl5.005_58 $ find lib -name \*.pm -exec grep -l ^__END__ {} \; | wc -l
109
perl5.005_58 $ find lib -name \*.pm -exec grep -l DATA {} \; | wc -l
20

It is probably to late to change __END__, so I think we need a new __ keyword
to denote the end and close the file.

--
Since you're clearly mad as a mongoose, I'll bid you good-day.
  -- Edmund to Captain Rum : Black Adder II "Potato"