Be more explicit when zip_stat_init should be used.

man/zip_source_function.mdoc

diff --git a/man/zip_source_function.mdoc b/man/zip_source_function.mdoc
index 65b11a9..81403aa 100644
--- a/man/zip_source_function.mdoc
+++ b/man/zip_source_function.mdoc
@@ -1,5 +1,5 @@
 .\" zip_source_function.mdoc -- create data source from function
-.\" Copyright (C) 2004-2011 Dieter Baron and Thomas Klausner
+.\" Copyright (C) 2004-2013 Dieter Baron and Thomas Klausner
 .\"
 .\" This file is part of libzip, a library to manipulate ZIP archives.
 .\" The authors can be contacted at <libzip@nih.at>
@@ -29,7 +29,7 @@
 .\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 .\" IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd March 22, 2011
+.Dd September 22, 2013
 .Dt ZIP_SOURCE_FUNCTION 3
 .Os
 .Sh NAME
@@ -84,11 +84,11 @@
 .It Dv ZIP_SOURCE_STAT
 Get meta information for the input data.
 .Ar data
-points to an initialized
+points to an allocated
 .Vt struct zip_stat ,
-which should be filled in.
-(See
-.Xr zip_stat_init 3 . )
+which should be initialized using
+.Xr zip_stat_init 3
+and then filled in.
 Information only available after the source has been read (e.g. size)
 can be omitted in an earlier call.
 Return sizeof(struct zip_stat) on success, \-1 on error.

man/zip_stat_init.mdoc

diff --git a/man/zip_stat_init.mdoc b/man/zip_stat_init.mdoc
index d31f5dd..488abea 100644
--- a/man/zip_stat_init.mdoc
+++ b/man/zip_stat_init.mdoc
@@ -1,5 +1,5 @@
 .\" zip_stat_init.mdoc -- init zip_stat structure
-.\" Copyright (C) 2006-2008 Dieter Baron and Thomas Klausner
+.\" Copyright (C) 2006-2013 Dieter Baron and Thomas Klausner
 .\"
 .\" This file is part of libzip, a library to manipulate ZIP archives.
 .\" The authors can be contacted at <libzip@nih.at>
@@ -29,7 +29,7 @@
 .\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 .\" IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd November 10, 2008
+.Dd September 22, 2013
 .Dt ZIP_STAT_INIT 3
 .Os
 .Sh NAME
@@ -53,6 +53,12 @@
 .Ar sb
 must be allocated before calling
 .Fn zip_stat_init .
+.Pp
+This function should be used by functions provided to
+.Xr zip_source_function 3
+when returning
+.Dv ZIP_SOURCE_STAT
+information to make sure all fields are initialized.
 .Sh RETURN VALUES
 If
 .Ar sb