syslog (priority, "event 0x%lx: %s", event, buf);
}
+=head1 CANCELLING LONG TRANSFERS
+
+Some operations can be cancelled by the caller while they are in
+progress. Currently only operations that involve uploading or
+downloading data can be cancelled (technically: operations that have
+C<FileIn> or C<FileOut> parameters in the generator).
+
+=head2 guestfs_user_cancel
+
+ void guestfs_user_cancel (guestfs_h *g);
+
+C<guestfs_user_cancel> cancels the current upload or download
+operation.
+
+Unlike most other libguestfs calls, this function is signal safe and
+thread safe. You can call it from a signal handler or from another
+thread, without needing to do any locking.
+
+The transfer that was in progress (if there is one) will stop shortly
+afterwards, and will return an error. The errno (see
+L</guestfs_last_errno>) is set to C<EINTR>, so you can test for this
+to find out if the operation was cancelled or failed because of
+another error.
+
+No cleanup is performed: for example, if a file was being uploaded
+then after cancellation there may be a partially uploaded file. It is
+the caller's responsibility to clean up if necessary.
+
+There are two common places that you might call C<guestfs_user_cancel>.
+
+In an interactive text-based program, you might call it from a
+C<SIGINT> signal handler so that pressing C<^C> cancels the current
+operation. (You also need to call L</guestfs_set_pgroup> so that
+child processes don't receive the C<^C> signal).
+
+In a graphical program, when the main thread is displaying a progress
+bar with a cancel button, wire up the cancel button to call this
+function.
+
=head1 PRIVATE DATA AREA
You can attach named pieces of private data to the libguestfs handle,
The L<virt-cat(1)>, L<virt-filesystems(1)> and L<virt-ls(1)> commands
and documentation.
+=item C<caution>
+
+Safety and liveness tests of components that libguestfs depends upon
+(not of libguestfs itself). Mainly this is for qemu and the kernel.
+
=item C<contrib>
Outside contributions, experimental parts.
L<virt-df(1)> command and documentation.
+=item C<edit>
+
+L<virt-edit(1)> command and documentation.
+
=item C<examples>
C API example code.
1,152,921,504,606,846,976 bytes) using sparse files backed by an XFS
host filesystem.
+Although libguestfs probably does not impose any limit, the underlying
+host storage will. If you store disk images on a host ext4
+filesystem, then the maximum size will be limited by the maximum ext4
+file size (currently 16 TB). If you store disk images as host logical
+volumes then you are limited by the maximum size of an LV.
+
+For the hugest disk image files, we recommend using XFS on the host
+for storage.
+
=head2 MAXIMUM SIZE OF A PARTITION
The MBR (ie. classic MS-DOS) partitioning scheme uses 32 bit sector