Inline::C output with printf problem

Cine has asked for the wisdom of the Perl Monks concerning the following question:

I'm trying to print a few lines from the C-part of my program, but it seems that there is some limit as to how much I can print? Can Anyone tell me why? Using simple trivial code, called a few hundred times:

void printit() {
  int i;
  printf(buf,"%d ",perm);
  for(i = 0; i < talks; i++)
    printf("%d ",res_a[i]);
  printf("\n");
}
[download]

If I run this in the shell it works fine (I get a ton of output)...
If I pipe it trough wc I get:

$perl test.pl | wc
     46    2859    8192
[download]

I then tried to call the output function twice for every time i would call it othervise and puf:

$ perl test.pl | wc
    113    7164   20480
[download]

As in I get the full output (twice) Why the sudden succes?!?

Ok so I must hit some magic barrier, but I cant find any other who have the same problem or any kind of documentation that would explain it. If I add an extra printf(" \n")(lots of spaces) it works.
As a second choice I then tried to call a perlfunction which print, but that keeps segfaulting?

void printit() {
  Inline_Stack_Vars;
  Inline_Stack_Reset;
  int i;
  int howmuch;
  char buf[1000];
  howmuch = sprintf(buf,"%d ",perm);
  for(i = 0; i < talks; i++) {
    howmuch+=sprintf(buf+howmuch,"%d ",res_a[i]);
  }
  buf[howmuch-1] = '\n';
  Inline_Stack_Push(newSVpvf("%s",buf));
  Inline_Stack_Done;
  perl_call_pv("main::printme",0);
  Inline_Stack_Void;
}
In Perl:
sub printme {
  print for $_[0];
}
[download]

T I M T O W T D I

Comment on Inline::C output with printf problem Select or Download Code

Replies are listed 'Best First'.
Re: Inline::C output with printf problem by sgifford (Prior) on Jul 04, 2003 at 04:33 UTC
Sounds like stdio buffering. What if you add `fflush(stdout);` [download] to the end of your C code?	[reply] [d/l]
Re: Re: Inline::C output with printf problem by Cine (Friar) on Jul 04, 2003 at 12:19 UTC
Already tried that, and sync and fsync. T I M T O W T D I	[reply] [d/l]


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