Fix documentation for vfs-type to reflect reality.

[libguestfs.git] / src / generator.ml

diff --git a/src/generator.ml b/src/generator.ml
index 986b0c5..8a6177c 100755 (executable)
--- a/src/generator.ml
+++ b/src/generator.ml
@@ -572,7 +572,7 @@ The first character of C<param> string must be a C<-> (dash).
 
 C<value> can be NULL.");
 
-  ("set_qemu", (RErr, [String "qemu"]), -1, [FishAlias "qemu"],
+  ("set_qemu", (RErr, [OptString "qemu"]), -1, [FishAlias "qemu"],
    [],
    "set the qemu binary",
    "\
@@ -604,7 +604,7 @@ Return the current qemu binary.
 This is always non-NULL.  If it wasn't set already, then this will
 return the default qemu binary name.");
 
-  ("set_path", (RErr, [String "searchpath"]), -1, [FishAlias "path"],
+  ("set_path", (RErr, [OptString "searchpath"]), -1, [FishAlias "path"],
    [],
    "set the search path",
    "\
@@ -791,8 +791,9 @@ against a completely different C<libguestfs.so> library.
 
 This call was added in version C<1.0.58>.  In previous
 versions of libguestfs there was no way to get the version
-number.  From C code you can use ELF weak linking tricks to find out if
-this symbol exists (if it doesn't, then it's an earlier version).
+number.  From C code you can use dynamic linker functions
+to find out if this symbol exists (if it doesn't, then
+it's an earlier version).
 
 The call returns a structure with four elements.  The first
 three (C<major>, C<minor> and C<release>) are numbers and
@@ -803,9 +804,13 @@ used for distro-specific information.
 To construct the original version string:
 C<$major.$minor.$release$extra>
 
+See also: L<guestfs(3)/LIBGUESTFS VERSION NUMBERS>.
+
 I<Note:> Don't use this call to test for availability
-of features.  Distro backports makes this unreliable.  Use
-C<guestfs_available> instead.");
+of features.  In enterprise distributions we backport
+features from later versions into earlier versions,
+making this an unreliable way to test for features.
+Use C<guestfs_available> instead.");
 
   ("set_selinux", (RErr, [Bool "selinux"]), -1, [FishAlias "selinux"],
    [InitNone, Always, TestOutputTrue (
@@ -3140,7 +3145,7 @@ Unknown file type
 
 =item '?'
 
-The L<readdir(3)> returned a C<d_type> field with an
+The L<readdir(3)> call returned a C<d_type> field with an
 unexpected value
 
 =back
@@ -3782,8 +3787,8 @@ was built (see C<appliance/kmod.whitelist.in> in the source).");
     )],
    "echo arguments back to the client",
    "\
-This command concatenate the list of C<words> passed with single spaces between
-them and returns the resulting string.
+This command concatenates the list of C<words> passed with single spaces
+between them and returns the resulting string.
 
 You can use this command to test the connection through to the daemon.
 
@@ -3885,12 +3890,13 @@ See also C<guestfs_realpath>.");
       [["vfs_type"; "/dev/sda1"]], "ext2")],
    "get the Linux VFS type corresponding to a mounted device",
    "\
-This command gets the block device type corresponding to
-a mounted device called C<device>.
+This command gets the filesystem type corresponding to
+the filesystem on C<device>.
 
-Usually the result is the name of the Linux VFS module that
-is used to mount this device (probably determined automatically
-if you used the C<guestfs_mount> call).");
+For most filesystems, the result is the name of the Linux
+VFS module which would be used to mount this filesystem
+if you mounted it without specifying the filesystem type.
+For example a string such as C<ext3> or C<ntfs>.");
 
   ("truncate", (RErr, [Pathname "path"]), 199, [],
    [InitBasicFS, Always, TestOutputStruct (
@@ -3910,8 +3916,13 @@ file must exist already.");
    "truncate a file to a particular size",
    "\
 This command truncates C<path> to size C<size> bytes.  The file
-must exist already.  If the file is smaller than C<size> then
-the file is extended to the required size with null bytes.");
+must exist already.
+
+If the current file size is less than C<size> then
+the file is extended to the required size with zero bytes.
+This creates a sparse file (ie. disk blocks are not allocated
+for the file until you write to it).  To create a non-sparse
+file of zeroes, use C<guestfs_fallocate64> instead.");
 
   ("utimens", (RErr, [Pathname "path"; Int64 "atsecs"; Int64 "atnsecs"; Int64 "mtsecs"; Int64 "mtnsecs"]), 201, [],
    [InitBasicFS, Always, TestOutputStruct (
@@ -4021,7 +4032,7 @@ C<names> is the list of files from this directory.
 
 On return you get a list of strings, with a one-to-one
 correspondence to the C<names> list.  Each string is the
-value of the symbol link.
+value of the symbolic link.
 
 If the C<readlink(2)> operation fails on any name, then
 the corresponding result string is the empty string C<\"\">.