fseek(...,SEEK_CUR) calls _fflush_r(ptr, fp) in read only mode
- Date: Fri, 1 Dec 2017 17:02:14 +0000 (UTC)
- From: "Xiaofeng Liu via cygwin" <cygwin@xxxxxxxxxx>
- Subject: fseek(...,SEEK_CUR) calls _fflush_r(ptr, fp) in read only mode
In ftello.c, it intentionally skipped fflush for read mode:
/* Find offset of underlying I/O object, then adjust for buffered bytes. Flush a write stream, since the offset may be altered if the stream is appending. Do not flush a read stream, since we must not lose the ungetc buffer. */ if (fp->_flags & __SWR) _fflush_r (ptr, fp);
But in fseeko.c, when fseek(..., SEEK_CUR) requires to get the current position first. But it calls _fflush_r(ptr, fp) in read mode, which screwed up the current position after fflush.
For my job, if I skip _fflush_r for read only mode in fseek(..., SEEK_CUR), the job runs OK.
Considering fseek(..., SEEK_CUR) is a basic call, could my understanding be wrong?
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