Re^3: write to /dev/full does not fail

[choroba]

Interestingly, if you print a lot, print itself will die:

perl -wE 'open my $F, ">", "/dev/full" or die "open:$!";
          for (1..10000) {
              print $F "line\n" or die "print:$!";
          };
          close $F or die "close:$!";
         '

print:No space left on device at -e line 3.

[Discipulus]

no, it seems to me it always, only dies on close:


#this not dies
perl -e 'open FH, ">", "/dev/full" or die $!; for (1..100) {print FH "
+line\n" or die $!;} '

#this too not dies
 perl -e '$|++;open FH, ">", "/dev/full" or die $!; for (1..100) {prin
+t FH "line\n" or die $!;} '

#only this dies, on close
 perl -e 'open FH, ">", "/dev/full" or die $!; for (1..100) {print FH 
+"line\n" or die $!;}; close FH or die $!'
No space left on device at -e line 1.

UPDATE: as suggested by choroba 100 are few (magic number seems to be 820):

# this still does not die
perl -e '$|++;open FH, ">", "/dev/full" or die $!; for (1..819) {print
+ FH "line\n" or die $!;} '


#but this dies!
 perl -e '$|++;open FH, ">", "/dev/full" or die $!; for (1..1000) {pri
+nt FH "line\n" or die $!;} '
No space left on device at -e line 1.

820 is to much? Perl becomes bored after 820 errors (not spotted)? is very patient: i'm hurted by second error.. ;=)

# perl -e 'print "$_\n" for 1..10000' | perl -ne '$num = <STDIN>;print
+ "$num:";open FH, ">", "/dev/full" or die $!; for (1..$num) {print FH
+ "line\n" or die $!;};close FH;'

..

:816
:818
:820
No space left on device at -e line 1, <STDIN> line 410.

[kschwab]

"line\n" is 5 bytes.

820 * 5 = 4100.

Buffer size for linux is 4096, so the write hits the actual device on your 820th iteration.