[Python-Dev] open('/dev/null').read() -> MemoryError (original) (raw)

Armin Rigo arigo at tunes.org
Mon Sep 27 22:05:33 CEST 2004

Hi,

On my system, which is admittedly an old Linux box (2.2 kernel), one test fails:

file('/dev/null').read() Traceback (most recent call last): File "", line 1, in ? MemoryError

This is because:

os.stat('/dev/null').stsize 4540321280L

This looks very broken indeed. I have no idea where this number comes from.
I'd also complain if I was asked to allocate a buffer large enough to hold that many bytes. If we cared, we could "enhance" the file.read() method to account for the possibility that maybe stat() lied; maybe it is desirable, instead of allocating huge amounts of memory, to revert to something like the following above some large threshold:

result = [] while 1: buf = f.read(16384) if not buf: return ''.join(result) result.append(buf)

Of course for genuinely large reads it's a disaster to have to allocate twice as much memory. Anyway I'm not sure we care about going around broken behaviour. I'm just wondering if os.stat() could lie in other situations too.

Armin

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