updated for version 7.3.831
Problem:    Clumsy to handle the situation that a variable does not exist.
Solution:   Add default value to getbufvar() et al. (Shougo Matsushita,
            Hirohito Higashi)
diff --git a/src/eval.c b/src/eval.c
index e1f29c4..480f214 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -7916,7 +7916,7 @@
     {"garbagecollect",	0, 1, f_garbagecollect},
     {"get",		2, 3, f_get},
     {"getbufline",	2, 3, f_getbufline},
-    {"getbufvar",	2, 2, f_getbufvar},
+    {"getbufvar",	2, 3, f_getbufvar},
     {"getchar",		0, 1, f_getchar},
     {"getcharmod",	0, 0, f_getcharmod},
     {"getcmdline",	0, 0, f_getcmdline},
@@ -7936,11 +7936,11 @@
     {"getqflist",	0, 0, f_getqflist},
     {"getreg",		0, 2, f_getreg},
     {"getregtype",	0, 1, f_getregtype},
-    {"gettabvar",	2, 2, f_gettabvar},
-    {"gettabwinvar",	3, 3, f_gettabwinvar},
+    {"gettabvar",	2, 3, f_gettabvar},
+    {"gettabwinvar",	3, 4, f_gettabwinvar},
     {"getwinposx",	0, 0, f_getwinposx},
     {"getwinposy",	0, 0, f_getwinposy},
-    {"getwinvar",	2, 2, f_getwinvar},
+    {"getwinvar",	2, 3, f_getwinvar},
     {"glob",		1, 3, f_glob},
     {"globpath",	2, 3, f_globpath},
     {"has",		1, 1, f_has},
@@ -11115,8 +11115,14 @@
     ++emsg_off;
     buf = get_buf_tv(&argvars[0]);
 
-    rettv->v_type = VAR_STRING;
-    rettv->vval.v_string = NULL;
+    if (argvars[2].v_type != VAR_UNKNOWN)
+	/* set the default value */
+	copy_tv(&argvars[2], rettv);
+    else
+    {
+	rettv->v_type = VAR_STRING;
+	rettv->vval.v_string = NULL;
+    }
 
     if (buf != NULL && varname != NULL)
     {
@@ -11785,7 +11791,11 @@
 	v = find_var_in_ht(&tp->tp_vars.dv_hashtab, varname, FALSE);
 	if (v != NULL)
 	    copy_tv(&v->di_tv, rettv);
+	else if (argvars[2].v_type != VAR_UNKNOWN)
+	    copy_tv(&argvars[2], rettv);
     }
+    else if (argvars[2].v_type != VAR_UNKNOWN)
+	copy_tv(&argvars[2], rettv);
 }
 
 /*
@@ -11907,8 +11917,14 @@
     varname = get_tv_string_chk(&argvars[off + 1]);
     ++emsg_off;
 
-    rettv->v_type = VAR_STRING;
-    rettv->vval.v_string = NULL;
+    if (argvars[off + 2].v_type != VAR_UNKNOWN)
+	/* set the default return value */
+	copy_tv(&argvars[off + 2], rettv);
+    else
+    {
+	rettv->v_type = VAR_STRING;
+	rettv->vval.v_string = NULL;
+    }
 
     if (win != NULL && varname != NULL)
     {
diff --git a/src/testdir/Make_amiga.mak b/src/testdir/Make_amiga.mak
index 19d8910..0e18992 100644
--- a/src/testdir/Make_amiga.mak
+++ b/src/testdir/Make_amiga.mak
@@ -32,7 +32,7 @@
 		test71.out test72.out test73.out test74.out test75.out \
 		test76.out test77.out test78.out test79.out test80.out \
 		test81.out test82.out test83.out test84.out test88.out \
-		test89.out test90.out
+		test89.out test90.out test91.out
 
 .SUFFIXES: .in .out
 
@@ -139,3 +139,4 @@
 test88.out: test88.in
 test89.out: test89.in
 test90.out: test90.in
+test91.out: test91.in
diff --git a/src/testdir/Make_dos.mak b/src/testdir/Make_dos.mak
index 99963e8..968cf6c 100644
--- a/src/testdir/Make_dos.mak
+++ b/src/testdir/Make_dos.mak
@@ -31,7 +31,7 @@
 		test74.out test75.out test76.out test77.out test78.out \
 		test79.out test80.out test81.out test82.out test83.out \
 		test84.out test85.out test86.out test87.out test88.out \
-		test89.out test90.out
+		test89.out test90.out test91.out
 
 SCRIPTS32 =	test50.out test70.out
 
diff --git a/src/testdir/Make_ming.mak b/src/testdir/Make_ming.mak
index 32d1db5..9d845ab 100644
--- a/src/testdir/Make_ming.mak
+++ b/src/testdir/Make_ming.mak
@@ -51,7 +51,7 @@
 		test74.out test75.out test76.out test77.out test78.out \
 		test79.out test80.out test81.out test82.out test83.out \
 		test84.out test85.out test86.out test87.out test88.out \
-		test89.out test90.out
+		test89.out test90.out test91.out
 
 SCRIPTS32 =	test50.out test70.out
 
diff --git a/src/testdir/Make_os2.mak b/src/testdir/Make_os2.mak
index 2f46a41..bddfd5e 100644
--- a/src/testdir/Make_os2.mak
+++ b/src/testdir/Make_os2.mak
@@ -32,7 +32,7 @@
 		test71.out test72.out test73.out test74.out test75.out \
 		test76.out test77.out test78.out test79.out test80.out \
 		test81.out test82.out test83.out test84.out test88.out \
-		test89.out test90.out
+		test89.out test90.out test91.out
 
 .SUFFIXES: .in .out
 
diff --git a/src/testdir/Make_vms.mms b/src/testdir/Make_vms.mms
index a0d29d7..f19dd5a 100644
--- a/src/testdir/Make_vms.mms
+++ b/src/testdir/Make_vms.mms
@@ -4,7 +4,7 @@
 # Authors:	Zoltan Arpadffy, <arpadffy@polarhome.com>
 #		Sandor Kopanyi,  <sandor.kopanyi@mailbox.hu>
 #
-# Last change:  2013 Feb 13
+# Last change:  2013 Feb 20
 #
 # This has been tested on VMS 6.2 to 8.3 on DEC Alpha, VAX and IA64.
 # Edit the lines in the Configuration section below to select.
@@ -77,7 +77,7 @@
 	 test71.out test72.out test74.out test75.out test76.out \
 	 test77.out test78.out test79.out test80.out test81.out \
 	 test82.out test83.out test84.out test88.out test89.out \
-	 test90.out
+	 test90.out test91.out
 
 # Known problems:
 # Test 30: a problem around mac format - unknown reason
diff --git a/src/testdir/Makefile b/src/testdir/Makefile
index 1920834..8b31b91 100644
--- a/src/testdir/Makefile
+++ b/src/testdir/Makefile
@@ -28,7 +28,7 @@
 		test74.out test75.out test76.out test77.out test78.out \
 		test79.out test80.out test81.out test82.out test83.out \
 		test84.out test85.out test86.out test87.out test88.out \
-		test89.out test90.out
+		test89.out test90.out test91.out
 
 SCRIPTS_GUI = test16.out
 
diff --git a/src/testdir/test91.in b/src/testdir/test91.in
new file mode 100644
index 0000000..1c8189d
--- /dev/null
+++ b/src/testdir/test91.in
@@ -0,0 +1,98 @@
+Tests for getbufvar(), getwinvar(), gettabvar() and gettabwinvar().
+vim: set ft=vim :
+
+STARTTEST
+:so small.vim
+:"
+:" test for getbufvar()
+:let b:var_num = 1234
+:let def_num = 5678
+:$put =string(getbufvar(1, 'var_num'))
+:$put =string(getbufvar(1, 'var_num', def_num))
+:$put =string(getbufvar(1, ''))
+:$put =string(getbufvar(1, '', def_num))
+:unlet b:var_num
+:$put =string(getbufvar(1, 'var_num', def_num))
+:$put =string(getbufvar(1, ''))
+:$put =string(getbufvar(1, '', def_num))
+:$put =string(getbufvar(9, ''))
+:$put =string(getbufvar(9, '', def_num))
+:unlet def_num
+:$put =string(getbufvar(1, '&autoindent'))
+:$put =string(getbufvar(1, '&autoindent', 1))
+:"
+:" test for getwinvar()
+:let w:var_str = "Dance"
+:let def_str = "Chance"
+:$put =string(getwinvar(1, 'var_str'))
+:$put =string(getwinvar(1, 'var_str', def_str))
+:$put =string(getwinvar(1, ''))
+:$put =string(getwinvar(1, '', def_str))
+:unlet w:var_str
+:$put =string(getwinvar(1, 'var_str', def_str))
+:$put =string(getwinvar(1, ''))
+:$put =string(getwinvar(1, '', def_str))
+:$put =string(getwinvar(9, ''))
+:$put =string(getwinvar(9, '', def_str))
+:$put =string(getwinvar(1, '&nu'))
+:$put =string(getwinvar(1, '&nu',  1))
+:unlet def_str
+:"
+:" test for gettabvar()
+:tabnew
+:tabnew
+:let t:var_list = [1, 2, 3]
+:let def_list = [4, 5, 6, 7]
+:tabrewind
+:$put =string(gettabvar(3, 'var_list'))
+:$put =string(gettabvar(3, 'var_list', def_list))
+:$put =string(gettabvar(3, ''))
+:$put =string(gettabvar(3, '', def_list))
+:tablast
+:unlet t:var_list
+:tabrewind
+:$put =string(gettabvar(3, 'var_list', def_list))
+:$put =string(gettabvar(9, ''))
+:$put =string(gettabvar(9, '', def_list))
+:$put =string(gettabvar(3, '&nu'))
+:$put =string(gettabvar(3, '&nu', def_list))
+:unlet def_list
+:tabonly
+:"
+:" test for gettabwinvar()
+:tabnew
+:tabnew
+:tabprev
+:split
+:split
+:wincmd w
+:vert split
+:wincmd w
+:let w:var_dict = {'dict': 'tabwin'}
+:let def_dict = {'dict2': 'newval'}
+:wincmd b
+:tabrewind
+:$put =string(gettabwinvar(2, 3, 'var_dict'))
+:$put =string(gettabwinvar(2, 3, 'var_dict', def_dict))
+:$put =string(gettabwinvar(2, 3, ''))
+:$put =string(gettabwinvar(2, 3, '', def_dict))
+:tabnext
+:3wincmd w
+:unlet w:var_dict
+:tabrewind
+:$put =string(gettabwinvar(2, 3, 'var_dict', def_dict))
+:$put =string(gettabwinvar(2, 3, ''))
+:$put =string(gettabwinvar(2, 3, '', def_dict))
+:$put =string(gettabwinvar(2, 9, ''))
+:$put =string(gettabwinvar(2, 9, '', def_dict))
+:$put =string(gettabwinvar(9, 3, ''))
+:$put =string(gettabwinvar(9, 3, '', def_dict))
+:unlet def_dict
+:$put =string(gettabwinvar(2, 3, '&nux'))
+:$put =string(gettabwinvar(2, 3, '&nux', 1))
+:tabonly
+:"
+:/^start/,$wq! test.out
+ENDTEST
+
+start:
diff --git a/src/testdir/test91.ok b/src/testdir/test91.ok
new file mode 100644
index 0000000..8777af8
--- /dev/null
+++ b/src/testdir/test91.ok
@@ -0,0 +1,45 @@
+start:
+1234
+1234
+{'var_num': 1234}
+{'var_num': 1234}
+5678
+{}
+{}
+''
+5678
+0
+0
+'Dance'
+'Dance'
+{'var_str': 'Dance'}
+{'var_str': 'Dance'}
+'Chance'
+{}
+{}
+''
+'Chance'
+0
+0
+[1, 2, 3]
+[1, 2, 3]
+''
+[4, 5, 6, 7]
+[4, 5, 6, 7]
+''
+[4, 5, 6, 7]
+''
+[4, 5, 6, 7]
+{'dict': 'tabwin'}
+{'dict': 'tabwin'}
+{'var_dict': {'dict': 'tabwin'}}
+{'var_dict': {'dict': 'tabwin'}}
+{'dict2': 'newval'}
+{}
+{}
+''
+{'dict2': 'newval'}
+''
+{'dict2': 'newval'}
+''
+1
diff --git a/src/version.c b/src/version.c
index 0881d92..6675d00 100644
--- a/src/version.c
+++ b/src/version.c
@@ -729,6 +729,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    831,
+/**/
     830,
 /**/
     829,