+#: ../src/guestfs.pod:1368
+msgid ""
+"Using L</guestfs_available> you can test availability of the following "
+"groups of functions. This test queries the appliance to see if the "
+"appliance you are currently using supports the functionality."
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1373
+msgid "@AVAILABILITY@"
+msgstr ""
+
+# type: =head2
+#: ../src/guestfs.pod:1375
+msgid "GUESTFISH supported COMMAND"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1377
+msgid ""
+"In L<guestfish(3)> there is a handy interactive command C<supported> which "
+"prints out the available groups and whether they are supported by this build "
+"of libguestfs. Note however that you have to do C<run> first."
+msgstr ""
+
+# type: =head2
+#: ../src/guestfs.pod:1382
+msgid "SINGLE CALLS AT COMPILE TIME"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1384
+msgid ""
+"Since version 1.5.8, C<E<lt>guestfs.hE<gt>> defines symbols for each C API "
+"function, such as:"
+msgstr ""
+
+# type: verbatim
+#: ../src/guestfs.pod:1387
+#, no-wrap
+msgid ""
+" #define LIBGUESTFS_HAVE_DD 1\n"
+"\n"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1389
+msgid "if L</guestfs_dd> is available."
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1391
+msgid ""
+"Before version 1.5.8, if you needed to test whether a single libguestfs "
+"function is available at compile time, we recommended using build tools such "
+"as autoconf or cmake. For example in autotools you could use:"
+msgstr ""
+
+# type: verbatim
+#: ../src/guestfs.pod:1396
+#, no-wrap
+msgid ""
+" AC_CHECK_LIB([guestfs],[guestfs_create])\n"
+" AC_CHECK_FUNCS([guestfs_dd])\n"
+"\n"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1399
+msgid ""
+"which would result in C<HAVE_GUESTFS_DD> being either defined or not defined "
+"in your program."
+msgstr ""
+
+# type: =head2
+#: ../src/guestfs.pod:1402
+msgid "SINGLE CALLS AT RUN TIME"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1404
+msgid ""
+"Testing at compile time doesn't guarantee that a function really exists in "
+"the library. The reason is that you might be dynamically linked against a "
+"previous I<libguestfs.so> (dynamic library) which doesn't have the call. "
+"This situation unfortunately results in a segmentation fault, which is a "
+"shortcoming of the C dynamic linking system itself."
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1411
+msgid ""
+"You can use L<dlopen(3)> to test if a function is available at run time, as "
+"in this example program (note that you still need the compile time check as "
+"well):"
+msgstr ""
+
+# type: verbatim
+#: ../src/guestfs.pod:1415
+#, no-wrap
+msgid ""
+" #include <stdio.h>\n"
+" #include <stdlib.h>\n"
+" #include <unistd.h>\n"
+" #include <dlfcn.h>\n"
+" #include <guestfs.h>\n"
+" \n"
+msgstr ""
+
+# type: verbatim
+#: ../src/guestfs.pod:1421
+#, no-wrap
+msgid ""
+" main ()\n"
+" {\n"
+" #ifdef LIBGUESTFS_HAVE_DD\n"
+" void *dl;\n"
+" int has_function;\n"
+" \n"
+msgstr ""
+
+# type: verbatim
+#: ../src/guestfs.pod:1427
+#, no-wrap
+msgid ""
+" /* Test if the function guestfs_dd is really available. */\n"
+" dl = dlopen (NULL, RTLD_LAZY);\n"
+" if (!dl) {\n"
+" fprintf (stderr, \"dlopen: %s\\n\", dlerror ());\n"
+" exit (EXIT_FAILURE);\n"
+" }\n"
+" has_function = dlsym (dl, \"guestfs_dd\") != NULL;\n"
+" dlclose (dl);\n"
+" \n"
+msgstr ""
+
+# type: verbatim
+#: ../src/guestfs.pod:1436
+#, no-wrap
+msgid ""
+" if (!has_function)\n"
+" printf (\"this libguestfs.so does NOT have guestfs_dd function\\n\");\n"
+" else {\n"
+" printf (\"this libguestfs.so has guestfs_dd function\\n\");\n"
+" /* Now it's safe to call\n"
+" guestfs_dd (g, \"foo\", \"bar\");\n"
+" */\n"
+" }\n"
+" #else\n"
+" printf (\"guestfs_dd function was not found at compile time\\n\");\n"
+" #endif\n"
+" }\n"
+"\n"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1449
+msgid ""
+"You may think the above is an awful lot of hassle, and it is. There are "
+"other ways outside of the C linking system to ensure that this kind of "
+"incompatibility never arises, such as using package versioning:"
+msgstr ""
+
+# type: verbatim
+#: ../src/guestfs.pod:1454
+#, no-wrap
+msgid ""
+" Requires: libguestfs >= 1.0.80\n"
+"\n"
+msgstr ""
+
+# type: =head1
+#: ../src/guestfs.pod:1456
+msgid "CALLS WITH OPTIONAL ARGUMENTS"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1458
+msgid ""
+"A recent feature of the API is the introduction of calls which take optional "
+"arguments. In C these are declared 3 ways. The main way is as a call which "
+"takes variable arguments (ie. C<...>), as in this example:"
+msgstr ""
+
+# type: verbatim
+#: ../src/guestfs.pod:1463
+#, no-wrap
+msgid ""
+" int guestfs_add_drive_opts (guestfs_h *g, const char *filename, ...);\n"
+"\n"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1465
+msgid ""
+"Call this with a list of optional arguments, terminated by C<-1>. So to "
+"call with no optional arguments specified:"
+msgstr ""
+
+# type: verbatim
+#: ../src/guestfs.pod:1468
+#, no-wrap
+msgid ""
+" guestfs_add_drive_opts (g, filename, -1);\n"
+"\n"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1470
+msgid "With a single optional argument:"
+msgstr ""
+
+# type: verbatim
+#: ../src/guestfs.pod:1472
+#, no-wrap
+msgid ""
+" guestfs_add_drive_opts (g, filename,\n"
+" GUESTFS_ADD_DRIVE_OPTS_FORMAT, \"qcow2\",\n"
+" -1);\n"
+"\n"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1476
+msgid "With two:"
+msgstr ""
+
+# type: verbatim
+#: ../src/guestfs.pod:1478
+#, no-wrap
+msgid ""
+" guestfs_add_drive_opts (g, filename,\n"
+" GUESTFS_ADD_DRIVE_OPTS_FORMAT, \"qcow2\",\n"
+" GUESTFS_ADD_DRIVE_OPTS_READONLY, 1,\n"
+" -1);\n"
+"\n"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1483
+msgid ""
+"and so forth. Don't forget the terminating C<-1> otherwise Bad Things will "
+"happen!"
+msgstr ""
+
+# type: =head2
+#: ../src/guestfs.pod:1486
+msgid "USING va_list FOR OPTIONAL ARGUMENTS"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1488
+msgid ""
+"The second variant has the same name with the suffix C<_va>, which works the "
+"same way but takes a C<va_list>. See the C manual for details. For the "
+"example function, this is declared:"
+msgstr ""
+
+# type: verbatim
+#: ../src/guestfs.pod:1492
+#, no-wrap
+msgid ""
+" int guestfs_add_drive_opts_va (guestfs_h *g, const char *filename,\n"
+" va_list args);\n"
+"\n"
+msgstr ""
+
+# type: =head2
+#: ../src/guestfs.pod:1495
+msgid "CONSTRUCTING OPTIONAL ARGUMENTS"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1497
+msgid ""
+"The third variant is useful where you need to construct these calls. You "
+"pass in a structure where you fill in the optional fields. The structure "
+"has a bitmask as the first element which you must set to indicate which "
+"fields you have filled in. For our example function the structure and call "
+"are declared:"
+msgstr ""
+
+# type: verbatim
+#: ../src/guestfs.pod:1503
+#, no-wrap
+msgid ""
+" struct guestfs_add_drive_opts_argv {\n"
+" uint64_t bitmask;\n"
+" int readonly;\n"
+" const char *format;\n"
+" /* ... */\n"
+" };\n"
+" int guestfs_add_drive_opts_argv (guestfs_h *g, const char *filename,\n"
+" const struct guestfs_add_drive_opts_argv *optargs);\n"
+"\n"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1512
+msgid "You could call it like this:"
+msgstr ""
+
+# type: verbatim
+#: ../src/guestfs.pod:1514
+#, no-wrap
+msgid ""
+" struct guestfs_add_drive_opts_argv optargs = {\n"
+" .bitmask = GUESTFS_ADD_DRIVE_OPTS_READONLY_BITMASK |\n"
+" GUESTFS_ADD_DRIVE_OPTS_FORMAT_BITMASK,\n"
+" .readonly = 1,\n"
+" .format = \"qcow2\"\n"
+" };\n"
+" \n"
+msgstr ""
+
+# type: verbatim
+#: ../src/guestfs.pod:1521
+#, no-wrap
+msgid ""
+" guestfs_add_drive_opts_argv (g, filename, &optargs);\n"
+"\n"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1523 ../src/guestfs-actions.pod:11
+#: ../src/guestfs-actions.pod:1842 ../fish/guestfish-actions.pod:9
+#: ../fish/guestfish-actions.pod:1255
+msgid "Notes:"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1529
+msgid "The C<_BITMASK> suffix on each option name when specifying the bitmask."
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1534
+msgid "You do not need to fill in all fields of the structure."
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1538
+msgid ""
+"There must be a one-to-one correspondence between fields of the structure "
+"that are filled in, and bits set in the bitmask."
+msgstr ""
+
+# type: =head2
+#: ../src/guestfs.pod:1543
+msgid "OPTIONAL ARGUMENTS IN OTHER LANGUAGES"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1545
+msgid ""
+"In other languages, optional arguments are expressed in the way that is "
+"natural for that language. We refer you to the language-specific "
+"documentation for more details on that."
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1549
+msgid "For guestfish, see L<guestfish(1)/OPTIONAL ARGUMENTS>."
+msgstr ""
+
+# type: =head2
+#: ../src/guestfs.pod:1551
+msgid "SETTING CALLBACKS TO HANDLE EVENTS"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1553
+msgid ""
+"The child process generates events in some situations. Current events "
+"include: receiving a log message, the child process exits."
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1556
+msgid ""
+"Use the C<guestfs_set_*_callback> functions to set a callback for different "
+"types of events."
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1559
+msgid ""
+"Only I<one callback of each type> can be registered for each handle. "
+"Calling C<guestfs_set_*_callback> again overwrites the previous callback of "
+"that type. Cancel all callbacks of this type by calling this function with "
+"C<cb> set to C<NULL>."
+msgstr ""
+
+# type: =head2
+#: ../src/guestfs.pod:1564
+msgid "guestfs_set_log_message_callback"
+msgstr ""
+
+# type: verbatim
+#: ../src/guestfs.pod:1566
+#, no-wrap
+msgid ""
+" typedef void (*guestfs_log_message_cb) (guestfs_h *g, void *opaque,\n"
+" char *buf, int len);\n"
+" void guestfs_set_log_message_callback (guestfs_h *g,\n"
+" guestfs_log_message_cb cb,\n"
+" void *opaque);\n"
+"\n"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1572
+msgid ""
+"The callback function C<cb> will be called whenever qemu or the guest writes "
+"anything to the console."
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1575
+msgid "Use this function to capture kernel messages and similar."
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1577
+msgid ""
+"Normally there is no log message handler, and log messages are just "
+"discarded."
+msgstr ""
+
+# type: =head2
+#: ../src/guestfs.pod:1580
+msgid "guestfs_set_subprocess_quit_callback"
+msgstr ""
+
+# type: verbatim
+#: ../src/guestfs.pod:1582
+#, no-wrap
+msgid ""
+" typedef void (*guestfs_subprocess_quit_cb) (guestfs_h *g, void *opaque);\n"
+" void guestfs_set_subprocess_quit_callback (guestfs_h *g,\n"
+" guestfs_subprocess_quit_cb cb,\n"
+" void *opaque);\n"
+"\n"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1587
+msgid ""
+"The callback function C<cb> will be called when the child process quits, "
+"either asynchronously or if killed by L</guestfs_kill_subprocess>. (This "
+"corresponds to a transition from any state to the CONFIG state)."
+msgstr ""
+
+# type: =head2
+#: ../src/guestfs.pod:1592
+msgid "guestfs_set_launch_done_callback"
+msgstr ""
+
+# type: verbatim
+#: ../src/guestfs.pod:1594
+#, no-wrap
+msgid ""
+" typedef void (*guestfs_launch_done_cb) (guestfs_h *g, void *opaque);\n"
+" void guestfs_set_launch_done_callback (guestfs_h *g,\n"
+" guestfs_launch_done_cb cb,\n"
+" void *opaque);\n"
+"\n"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1599
+msgid ""
+"The callback function C<cb> will be called when the child process becomes "
+"ready first time after it has been launched. (This corresponds to a "
+"transition from LAUNCHING to the READY state)."
+msgstr ""
+
+# type: =head2
+#: ../src/guestfs.pod:1603
+msgid "guestfs_set_close_callback"
+msgstr ""
+
+# type: verbatim
+#: ../src/guestfs.pod:1605
+#, no-wrap
+msgid ""
+" typedef void (*guestfs_close_cb) (guestfs_h *g, void *opaque);\n"
+" void guestfs_set_close_callback (guestfs_h *g,\n"
+" guestfs_close_cb cb,\n"
+" void *opaque);\n"
+"\n"
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1610
+msgid ""
+"The callback function C<cb> will be called while the handle is being closed "
+"(synchronously from L</guestfs_close>)."
+msgstr ""
+
+# type: textblock
+#: ../src/guestfs.pod:1613