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.Dd October 25, 2003 .Dt FDATASYNC 2 .Os .Sh NAME .Nm fdatasync .Nd synchronize the data of a file .Sh LIBRARY .Lb libc .Sh SYNOPSIS n unistd.h .Ft int .Fn fdatasync "int fd" .Sh DESCRIPTION The .Fn fdatasync function forces all modified data associated with the file descriptor .Fa fd to be flushed to stable storage.
p The functionality is as described for .Xr fsync 2 , with the exception that file status information need not be synchronized, which may result in a performance gain, compared to .Xr fsync 2 . This behaviour is commonly known as f -symbolic synchronized I/O data integrity completion. .Ef .Sh RETURN VALUES A value of 0 is returned on success. Otherwise, a value -1 is returned and .Va errno is set to indicate the error. .Sh ERRORS The .Fn fdatasync function will fail if: l -tag -width Er t Bq Er EBADF The .Fa fd argument is not a valid file descriptor. t Bq Er EINVAL This implementation does not support synchronized I/O for this file. t Bq Er ENOSYS The .Fn fdatasync function is not supported by this implementation. .El
p In the event that any of the I/O operations to be performed fail, .Fn fdatasync returns the error conditions defined for .Xr read 2 and .Xr write 2 , and outstanding I/O operations are not guaranteed to have been completed. .Sh SEE ALSO .Xr fsync 2 , .Xr open 2 , .Xr read 2 , .Xr write 2 .Sh STANDARDS The .Fn fdatasync function conforms to .St -p1003.1-2008 .
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