Clarify documentation on distro backports in version command.

[libguestfs.git] / src / generator.ml

diff --git a/src/generator.ml b/src/generator.ml
index 1e7e90c..c6a1262 100755 (executable)
--- a/src/generator.ml
+++ b/src/generator.ml
@@ -807,9 +807,13 @@ 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 (
@@ -3925,8 +3929,13 @@ 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 (
@@ -4036,7 +4045,7 @@ 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<\"\">.