mirror of https://github.com/python/cpython
26800cf25a
lseek() always returns 0 for character pseudo-devices like `/dev/urandom` (for other non-regular files, e.g. `/dev/stdin`, it always returns -1, to which CPython reacts by raising appropriate exceptions). They are thus technically seekable despite not having seek semantics. When calling read() on e.g. an instance of `io.BufferedReader` that wraps such a file, `BufferedReader` reads ahead, filling its buffer, creating a discrepancy between the number of bytes read and the internal `tell()` always returning 0, which previously resulted in e.g. `BufferedReader.tell()` or `BufferedReader.seek()` being able to return positions < 0 even though these are supposed to be always >= 0. Invariably keep the return value non-negative by returning max(former_return_value, 0) instead, and add some corresponding tests. |
||
|---|---|---|
| .. | ||
| clinic | ||
| _iomodule.c | ||
| _iomodule.h | ||
| bufferedio.c | ||
| bytesio.c | ||
| fileio.c | ||
| iobase.c | ||
| stringio.c | ||
| textio.c | ||
| winconsoleio.c | ||