mingw: adds (partial) implementations of pread/pwrite #6015
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This saves some lines of code and a few thousand syscalls per event.
mcevoypeter
suggested changes
Sep 28, 2022
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| overlapped.OffsetHigh = (sizeof(off_t) <= sizeof(DWORD)) ? | ||
| (DWORD)0 : (DWORD)((offset >> 32) & 0xFFFFFFFFL); | ||
| overlapped.Offset = (sizeof(off_t) <= sizeof(DWORD)) ? | ||
| (DWORD)offset : (DWORD)(offset & 0xFFFFFFFFL); |
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Why not use a macro to avoid repeating 0xFFFFFFFFL multiple times?
#define DWORD_MASK 0xFFFFFFFFLThere was a problem hiding this comment.
This code is entirely consistent with the conventions used throughout compat.c. There are many things about that file that I would change if I was going to refactor it, but all that I'm doing here is adding these two wrapper functions.
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| { | ||
| c3_assert(0); | ||
| } |
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Let's print strerror(errno) here if pwrite() fails.
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This PR builds on #5889. It's a draft due to conflicts, and should wait to be reconciled with #6003.
The implementations are "partial" because
ReadFile()andWriteFile()update the file position after i/o completion -- these are not spec-conformant implementations, but are fit for our single-threaded use-cases (so long as calls to their non-positioned counterparts aren't intermingled on the same file description).