Re "There are a lot of scenarios", Maybe, but the discussion at hand is about reading the entire file.

I used 8*1024 because read reads in 8 KiB chunks anyway. 

$ perl -e'print "x" x 100_000' \
| strace perl -e'read(\*STDIN, my $buf, 100_000)' 2>&1 \
| grep -P 'read\(0,'
read(0, "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"..., 8192) = 8192
read(0, "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"..., 8192) = 8192
read(0, "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"..., 8192) = 8192
read(0, "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"..., 8192) = 8192
read(0, "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"..., 8192) = 8192
read(0, "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"..., 8192) = 8192
read(0, "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"..., 8192) = 8192
read(0, "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"..., 8192) = 8192
read(0, "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"..., 8192) = 8192
read(0, "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"..., 8192) = 8192
read(0, "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"..., 8192) = 8192
read(0, "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"..., 8192) = 8192
read(0, "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"..., 8192) = 1696

[download]

But the parameter refers to the number of character to return, which could be different than the number of bytes read if an :encoding layer is used. So really, the number I picked is nothing to praise. If you want efficiency, it's probably best to use sysread with a very large number and decode afterwards.

In reply to Re^8: Error binmode() on unopened filehandle by ikegami
in thread Error binmode() on unopened filehandle by RedJeep

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