Section: Linux Programmer's Manual (2)
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sync, syncfs - commit buffer cache to disk
int syncfs(int fd);
Feature Test Macro Requirements for glibc (see
_BSD_SOURCE || _XOPEN_SOURCE >= 500 ||
_XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
causes all buffered modifications to file metadata and data to be
written to the underlying filesystems.
but synchronizes just the filesystem containing file
referred to by the open file descriptor
returns 0 on success;
on error, it returns -1 and sets
to indicate the error.
is always successful.
can fail for at least the following reason:
is not a valid file descriptor.
first appeared in Linux 2.6.39;
library support was added to glibc in version 2.14.
SVr4, 4.3BSD, POSIX.1-2001.
Since glibc 2.2.2, the Linux prototype for
is as listed above,
following the various standards.
In glibc 2.2.1 and earlier,
it was "int sync(void)", and
always returned 0.
According to the standard specification (e.g., POSIX.1-2001),
schedules the writes, but may return before the actual
writing is done.
However, since version 1.3.20 Linux does actually wait.
(This still does not guarantee data integrity: modern disks have
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- RETURN VALUE
- CONFORMING TO
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