diff --git a/src/cmd/builtin/pty.c b/src/cmd/builtin/pty.c
index ad932a3747fe..b3f31ade07f9 100644
--- a/src/cmd/builtin/pty.c
+++ b/src/cmd/builtin/pty.c
@@ -512,7 +512,7 @@ masterline(Sfio_t* mp, Sfio_t* lp, char* prompt, int must, int timeout, Master_t
 	char*		t;
 	ssize_t		n;
 	ssize_t		a;
-	size_t		promptlen;
+	size_t		promptlen = 0;
 	ptrdiff_t	d;
 	char		promptbuf[64];
 
@@ -782,6 +782,8 @@ dialogue(Sfio_t* mp, Sfio_t* lp, int delay, int timeout)
 	    !(master->buf = vmnewof(vm, 0, char, 2 * SF_BUFSIZE, 0)))
 	{
 		error(ERROR_SYSTEM|2, "out of space");
+		id = 0;
+		line = 0;
 		goto done;
 	}
 	master->vm = vm;
diff --git a/src/cmd/ksh93/edit/edit.c b/src/cmd/ksh93/edit/edit.c
index ec9725b59f97..04d710b19ae4 100644
--- a/src/cmd/ksh93/edit/edit.c
+++ b/src/cmd/ksh93/edit/edit.c
@@ -1406,12 +1406,12 @@ int	ed_internal(const char *src, genchar *dest)
 int	ed_external(const genchar *src, char *dest)
 {
 	register genchar wc;
-	register int c,size;
 	register char *dp = dest;
 	char *dpmax = dp+sizeof(genchar)*MAXLINE-2;
 	if((char*)src == dp)
 	{
-		char buffer[MAXLINE*sizeof(genchar)];
+		int c;
+		char buffer[MAXLINE*sizeof(genchar)] = "";
 		c = ed_external(src,buffer);
 
 #ifdef _lib_wcscpy
@@ -1423,6 +1423,7 @@ int	ed_external(const genchar *src, char *dest)
 	}
 	while((wc = *src++) && dp<dpmax)
 	{
+		ssize_t size;
 		if((size = mbconv(dp, wc)) < 0)
 		{
 			/* copy the character as is */
diff --git a/src/cmd/ksh93/sh/init.c b/src/cmd/ksh93/sh/init.c
index 279c6ab613cf..3a0271b928e3 100644
--- a/src/cmd/ksh93/sh/init.c
+++ b/src/cmd/ksh93/sh/init.c
@@ -1176,7 +1176,7 @@ Shell_t *sh_init(register int argc,register char *argv[], Shinit_f userinit)
 	static int beenhere;
 	Shell_t	*shp;
 	register int n;
-	int type;
+	int type = 0;
 	char *save_envmarker;
 	static char *login_files[2];
 	memfatal();
@@ -1846,7 +1846,7 @@ Dt_t *sh_inittree(Shell_t *shp,const struct shtable2 *name_vals)
 	register const struct shtable2 *tp;
 	register unsigned n = 0;
 	register Dt_t *treep;
-	Dt_t *base_treep, *dict;
+	Dt_t *base_treep, *dict = 0;
 	for(tp=name_vals;*tp->sh_name;tp++)
 		n++;
 	np = (Namval_t*)calloc(n,sizeof(Namval_t));
diff --git a/src/cmd/ksh93/sh/macro.c b/src/cmd/ksh93/sh/macro.c
index 9f051befa5e9..5a740b4f0f3f 100644
--- a/src/cmd/ksh93/sh/macro.c
+++ b/src/cmd/ksh93/sh/macro.c
@@ -1803,7 +1803,7 @@ static int varsub(Mac_t *mp)
 		int ofs_size = 0;
 		regoff_t match[2*(MATCH_MAX+1)];
 		int nmatch, nmatch_prev, vsize_last;
-		char *vlast;
+		char *vlast = NIL(char*);
 		while(1)
 		{
 			if(!v)
diff --git a/src/cmd/ksh93/sh/name.c b/src/cmd/ksh93/sh/name.c
index 1b77537003b4..5ebf6abbed1d 100644
--- a/src/cmd/ksh93/sh/name.c
+++ b/src/cmd/ksh93/sh/name.c
@@ -1305,7 +1305,7 @@ Namval_t *nv_open(const char *name, Dt_t *root, int flags)
 	const char		*msg = e_varname;
 	char			*fname = 0;
 	int			offset = staktell();
-	Dt_t			*funroot;
+	Dt_t			*funroot = NIL(Dt_t*);
 #if NVCACHE
 	struct Cache_entry	*xp;
 #endif
@@ -1779,7 +1779,7 @@ void nv_putval(register Namval_t *np, const char *string, int flags)
 	else
 	{
 		const char *tofree=0;
-		int offset,append;
+		int offset=0,append;
 #if _lib_pathnative
 		char buff[PATH_MAX];
 #endif /* _lib_pathnative */
diff --git a/src/cmd/ksh93/sh/nvdisc.c b/src/cmd/ksh93/sh/nvdisc.c
index 70e65e2d0a7e..8de284f785e3 100644
--- a/src/cmd/ksh93/sh/nvdisc.c
+++ b/src/cmd/ksh93/sh/nvdisc.c
@@ -453,7 +453,7 @@ static Sfdouble_t lookupn(Namval_t *np, Namfun_t *handle)
 char *nv_setdisc(register Namval_t* np,register const char *event,Namval_t *action,register Namfun_t *fp)
 {
 	register struct vardisc *vp = (struct vardisc*)np->nvfun;
-	register int type;
+	register int type = -1;
 	char *empty = "";
 	while(vp)
 	{
@@ -509,6 +509,8 @@ char *nv_setdisc(register Namval_t* np,register const char *event,Namval_t *acti
 		}
 		return(NIL(char*));
 	}
+	if (type < 0)
+		return(NIL(char*));
 	/* Handle GET/SET/APPEND/UNSET disc */
 	if(vp && vp->fun.disc->putval!=assign)
 		vp = 0;
diff --git a/src/cmd/ksh93/sh/nvtree.c b/src/cmd/ksh93/sh/nvtree.c
index dcfc9add68b3..4e5c375b6cf4 100644
--- a/src/cmd/ksh93/sh/nvtree.c
+++ b/src/cmd/ksh93/sh/nvtree.c
@@ -557,7 +557,7 @@ void nv_outnode(Namval_t *np, Sfio_t* out, int indent, int special)
 	char		*fmtq,*ep,*xp;
 	Namval_t	*mp;
 	Namarr_t	*ap = nv_arrayptr(np);
-	int		scan,tabs=0,c,more,associative = 0;
+	int		scan=0,tabs=0,c,more,associative = 0;
 	int		saveI = Indent;
 	Indent = indent;
 	if(ap)
@@ -670,7 +670,7 @@ void nv_outnode(Namval_t *np, Sfio_t* out, int indent, int special)
 
 static void outval(char *name, const char *vname, struct Walk *wp)
 {
-	register Namval_t *np, *nq, *last_table=wp->shp->last_table;
+	register Namval_t *np, *nq=0, *last_table=wp->shp->last_table;
         register Namfun_t *fp;
 	int isarray=0, special=0,mode=0;
 	if(*name!='.' || vname[strlen(vname)-1]==']')
diff --git a/src/cmd/ksh93/sh/nvtype.c b/src/cmd/ksh93/sh/nvtype.c
index 040730c7f7dd..61cc371bc99c 100644
--- a/src/cmd/ksh93/sh/nvtype.c
+++ b/src/cmd/ksh93/sh/nvtype.c
@@ -826,9 +826,10 @@ void nv_newtype(Namval_t *mp)
 Namval_t *nv_mktype(Namval_t **nodes, int numnodes)
 {
 	Namval_t	*mp=nodes[0], *bp=0, *np, *nq, **mnodes=nodes;
-	int		i,j,k,m,n,nd=0,nref=0,iref=0,inherit=0;
+	int		i,j,k,nd=0,nref=0,iref=0,inherit=0;
 	int		size=sizeof(NV_DATA), dsize=0, nnodes;
-	size_t		offset=0;
+	size_t		offset=0,m;
+	ssize_t		n;
 	char		*name=0, *cp, *sp, **help;
 	Namtype_t	*pp,*qp=0,*dp,*tp;
 	Dt_t		*root = nv_dict(mp);
@@ -841,6 +842,7 @@ Namval_t *nv_mktype(Namval_t **nodes, int numnodes)
 		_nv_unset(nodes[0],NV_RDONLY);
 		errormsg(SH_DICT,ERROR_exit(1),e_badtypedef,cp);
 	}
+	n=strlen(nodes[1]->nvname);
 	for(nnodes=1,i=1; i <numnodes; i++)
 	{
 		np=nodes[i];
diff --git a/src/cmd/ksh93/sh/parse.c b/src/cmd/ksh93/sh/parse.c
index 063d21e7a49d..734d2b1d20d1 100644
--- a/src/cmd/ksh93/sh/parse.c
+++ b/src/cmd/ksh93/sh/parse.c
@@ -302,7 +302,7 @@ static Shnode_t *getanode(Lex_t *lp, struct argnod *ap)
  */
 static Shnode_t	*makelist(Lex_t *lexp, int type, Shnode_t *l, Shnode_t *r)
 {
-	register Shnode_t	*t;
+	register Shnode_t	*t = NIL(Shnode_t*);
 	if(!l || !r)
 		sh_syntax(lexp);
 	else
@@ -808,7 +808,7 @@ static Shnode_t *funct(Lex_t *lexp)
 		{
 			struct comnod	*ac;
 			char		*cp, **argv, **argv0;
-			int		c;
+			int		c=-1;
 			t->funct.functargs = ac = (struct comnod*)simple(lexp,SH_NOIO|SH_FUNDEF,NIL(struct ionod*));
 			if(ac->comset || (ac->comtyp&COMSCAN))
 				errormsg(SH_DICT,ERROR_exit(3),e_lexsyntax4,lexp->sh->inlineno);
diff --git a/src/cmd/ksh93/sh/xec.c b/src/cmd/ksh93/sh/xec.c
index d460a9fa03a5..23526098ec20 100644
--- a/src/cmd/ksh93/sh/xec.c
+++ b/src/cmd/ksh93/sh/xec.c
@@ -1426,7 +1426,7 @@ int sh_exec(register const Shnode_t *t, int flags)
 					Namval_t node;
 #endif /* SHOPT_NAMESPACE */
 					struct Namref	nr;
-					long		mode;
+					long		mode = 0;
 					register struct slnod *slp;
 					if(!np->nvalue.ip)
 					{
@@ -1771,8 +1771,8 @@ int sh_exec(register const Shnode_t *t, int flags)
 		     * don't create a new process, just
 		     * save and restore io-streams
 		     */
-			pid_t	pid;
-			int 	jmpval, waitall;
+			pid_t	pid = 0;
+			int 	jmpval, waitall = 0;
 			int 	simple = (t->fork.forktre->tre.tretyp&COMMSK)==TCOM;
 			struct checkpt *buffp = (struct checkpt*)stkalloc(shp->stk,sizeof(struct checkpt));
 			if(shp->subshell)
@@ -2162,7 +2162,7 @@ int sh_exec(register const Shnode_t *t, int flags)
 			Shnode_t *tt = t->wh.whtre;
 #if SHOPT_FILESCAN
 			Sfio_t *iop=0;
-			int savein;
+			int savein=-1;
 #endif /*SHOPT_FILESCAN*/
 #if SHOPT_OPTIMIZE
 			int  jmpval = ((struct checkpt*)shp->jmplist)->mode;
@@ -2579,7 +2579,7 @@ int sh_exec(register const Shnode_t *t, int flags)
 			else
 			{
 				register int traceon=0;
-				register char *right;
+				register char *right = 0;
 				register char *trap;
 				char *argv[6];
 				n = type>>TSHIFT;
@@ -2613,7 +2613,7 @@ int sh_exec(register const Shnode_t *t, int flags)
 				}
 				else if(type&TBINARY)
 				{
-					char *op;
+					char *op = 0;
 					int pattern = 0;
 					if(trap || traceon)
 						op = (char*)(shtab_testops+(n&037)-1)->sh_name;
@@ -3277,11 +3277,11 @@ static void sh_funct(Shell_t *shp,Namval_t *np,int argn, char *argv[],struct arg
 int sh_fun(Namval_t *np, Namval_t *nq, char *argv[])
 {
 	Shell_t		*shp = sh_getinterp();
-	register int offset;
+	register int offset = 0;
 	register char *base;
 	Namval_t node;
 	struct Namref	nr;
-	long		mode;
+	long		mode = 0;
 	char		*prefix = shp->prefix;
 	int n=0;
 	char *av[3];
diff --git a/src/lib/libast/sfio/sfstrtof.h b/src/lib/libast/sfio/sfstrtof.h
index 4b2f40076079..4d41e79d31b1 100644
--- a/src/lib/libast/sfio/sfstrtof.h
+++ b/src/lib/libast/sfio/sfstrtof.h
@@ -211,8 +211,8 @@ S2F_function(str, end) char* str; char** end;
 	int			decimal = 0;
 	int			thousand = 0;
 	int			part = 0;
-	int			back_part;
-	S2F_batch		back_n;
+	int			back_part = 0;
+	S2F_batch		back_n = 0;
 	S2F_number		v;
 	S2F_number		p;
 	S2F_part_t		parts[16];
diff --git a/src/lib/libast/sfio/sftable.c b/src/lib/libast/sfio/sftable.c
index 9c0de46e6896..b7395d776b4a 100644
--- a/src/lib/libast/sfio/sftable.c
+++ b/src/lib/libast/sfio/sftable.c
@@ -53,7 +53,7 @@ int		type;	/* >0: scanf, =0: printf, -1: internal	*/
 #endif
 {
 	int		base, fmt, flags, dot, width, precis;
-	ssize_t		n_str, size;
+	ssize_t		n_str, size = 0;
 	char		*t_str, *sp;
 	int		v, n, skip, dollar, decimal, thousand;
 	Sffmt_t		savft;
diff --git a/src/lib/libast/sfio/sfvprintf.c b/src/lib/libast/sfio/sfvprintf.c
index 90014f24c52c..227fd0f350e9 100644
--- a/src/lib/libast/sfio/sfvprintf.c
+++ b/src/lib/libast/sfio/sfvprintf.c
@@ -101,7 +101,7 @@ char*	form;		/* format to use	*/
 va_list	args;		/* arg list if !argf	*/
 #endif
 {
-	int		n, v, w, k, n_s, base, fmt, flags;
+	int		n, v=0, w, k, n_s, base, fmt, flags;
 	Sflong_t	lv;
 	char		*sp, *ssp, *endsp, *ep, *endep;
 	int		dot, width, precis, sign, decpt;
@@ -129,7 +129,7 @@ va_list	args;		/* arg list if !argf	*/
 	int		decimal = 0, thousand = 0;
 
 #if _has_multibyte
-	wchar_t*	wsp;
+	wchar_t*	wsp = 0;
 	SFMBDCL(fmbs)			/* state of format string	*/
 	SFMBDCL(mbs)			/* state of some string		*/
 #ifdef mbwidth
diff --git a/src/lib/libast/string/stropt.c b/src/lib/libast/string/stropt.c
index 91bd35138040..12664a8a9082 100644
--- a/src/lib/libast/string/stropt.c
+++ b/src/lib/libast/string/stropt.c
@@ -60,13 +60,13 @@ stropt(const char* as, const void* tab, int siz, int(*f)(void*, const void*, int
 	register char*	v;
 	register char*	t;
 	char**		p;
-	char*		u;
+	char*		u = 0;
 	char*		x;
 	char*		e;
 	int		n;
 	int		ql;
 	int		qr;
-	int		qc;
+	int		qc = 0;
 
 	if (!as) n = 0;
 	else if (!(x = s = strdup(as))) n = -1;
diff --git a/src/lib/libast/string/strtoi.h b/src/lib/libast/string/strtoi.h
index 91799c6f6c12..6275c23c8d61 100644
--- a/src/lib/libast/string/strtoi.h
+++ b/src/lib/libast/string/strtoi.h
@@ -230,13 +230,13 @@ S2I_function(a, e, base) const char* a; char** e; int base;
 #endif
 	register S2I_unumber	n;
 	register S2I_unumber	x;
-	register int		c;
+	register int		c = 0;
 	register int		shift;
 	register unsigned char*	p;
 	register unsigned char*	cv;
 	unsigned char*		b;
 	unsigned char*		k;
-	S2I_unumber		v;
+	S2I_unumber		v = 0;
 #if S2I_multiplier
 	register int		base;
 #endif