fdatasync(2) [netbsd man page]

FDATASYNC(2)						      BSD System Calls Manual						      FDATASYNC(2)

NAME

     fdatasync -- synchronize the data of a file

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <unistd.h>

     int
     fdatasync(int fd);

DESCRIPTION

     The fdatasync() function forces all modified data associated with the file descriptor fd to be flushed to stable storage.

     The functionality is as described for fsync(2), with the exception that file status information need not be synchronized, which may result in
     a performance gain, compared to fsync(2).	This behaviour is commonly known as synchronized I/O data integrity completion.

RETURN VALUES

     A value of 0 is returned on success.  Otherwise, a value -1 is returned and errno is set to indicate the error.

ERRORS

     The fdatasync() function will fail if:

     [EBADF]		The fd argument is not a valid file descriptor open for writing.

     [EINVAL]		This implementation does not support synchronized I/O for this file.

     [ENOSYS]		The fdatasync() function is not supported by this implementation.

     In the event that any of the I/O operations to be performed fail, fdatasync() returns the error conditions defined for read(2) and write(2),
     and outstanding I/O operations are not guaranteed to have been completed.

SEE ALSO

     fsync(2), open(2), read(2), write(2)

STANDARDS

     The fdatasync() function conforms to IEEE Std 1003.1b-1993 (``POSIX.1'').

BSD
								 October 25, 2003							       BSD

fdatasync(2)							System Calls Manual						      fdatasync(2)

NAME

       fdatasync -  Writes data changes in a file to permanent storage

SYNOPSIS

       #include <unistd.h>

       int fdatasync (	    int fildes );

PARAMETERS

       Specifies a valid open file descriptor.

DESCRIPTION

       The  fdatasync function causes system buffers containing a file's modified data to be written to permanent storage.  The fdatasync function
       does not return until the operation has been completed. The fdatasync function provides data integrity, ensuring  that  data  in  permanent
       storage	is  identical  to data in the buffer. However, use of fdatasync does not guarantee that file control information such as owner and
       modification time has been updated to permanent storage (see the fsync function).

NOTES

       The file identified by the fildes parameter must be open for writing when the fdatasync function is issued or the call will fail.

RETURN VALUES

       Upon successful completion, the fdatasync function returns a value of 0 (zero). If the fdatasync function fails, a value of -1 is  returned
       and errno is set to indicate the error. If fdatasync fails, outstanding I/O operations are not guaranteed to have been completed.

ERRORS

       If the fdatasync function fails, errno may be set to one of the following values:

       [EBADF]	      The fildes parameter is not a valid file descriptor.

       [EINVAL]       The fildes parameter does not refer to a file on which this operation is possible.

       If any queued I/O operations fail, the fdatasync function returns error conditions defined for the read and write functions.

RELATED INFORMATION

       Functions: fcntl(2), fsync(2), open(2), read(2), sync(2), write(2) delim off

																      fdatasync(2)