diff --git a/bin/echo/echo.c b/bin/echo/echo.c
index 71fecd4ca7da..96fe84777eed 100644
--- a/bin/echo/echo.c
+++ b/bin/echo/echo.c
@@ -49,12 +49,8 @@ static const char rcsid[] =
 #include <stdlib.h>
 #include <string.h>
 
-int main __P((int, char *[]));
-
 int
-main(argc, argv)
-	int argc __unused;
-	char *argv[];
+main(int argc __unused, char *argv[])
 {
 	int nflag;
 
diff --git a/bin/ed/buf.c b/bin/ed/buf.c
index 01f722bf0993..b70346c3b170 100644
--- a/bin/ed/buf.c
+++ b/bin/ed/buf.c
@@ -45,8 +45,7 @@ line_t buffer_head;			/* incore buffer */
 /* get_sbuf_line: get a line of text from the scratch file; return pointer
    to the text */
 char *
-get_sbuf_line(lp)
-	line_t *lp;
+get_sbuf_line(line_t *lp)
 {
 	static char *sfbuf = NULL;	/* buffer */
 	static int sfbufsz = 0;		/* buffer size */
@@ -81,8 +80,7 @@ get_sbuf_line(lp)
 /* put_sbuf_line: write a line of text to the scratch file and add a line node
    to the editor buffer;  return a pointer to the end of the text */
 const char *
-put_sbuf_line(cs)
-	const char *cs;
+put_sbuf_line(const char *cs)
 {
 	line_t *lp;
 	int len, ct;
@@ -128,8 +126,7 @@ put_sbuf_line(cs)
 
 /* add_line_node: add a line node in the editor buffer after the current line */
 void
-add_line_node(lp)
-	line_t *lp;
+add_line_node(line_t *lp)
 {
 	line_t *cp;
 
@@ -142,8 +139,7 @@ add_line_node(lp)
 
 /* get_line_node_addr: return line number of pointer */
 long
-get_line_node_addr(lp)
-	line_t *lp;
+get_line_node_addr(line_t *lp)
 {
 	line_t *cp = &buffer_head;
 	long n = 0;
@@ -160,8 +156,7 @@ get_line_node_addr(lp)
 
 /* get_addressed_line_node: return pointer to a line node in the editor buffer */
 line_t *
-get_addressed_line_node(n)
-	long n;
+get_addressed_line_node(long n)
 {
 	static line_t *lp = &buffer_head;
 	static long on = 0;
@@ -196,7 +191,7 @@ char sfn[15] = "";				/* scratch file name */
 
 /* open_sbuf: open scratch file */
 int
-open_sbuf()
+open_sbuf(void)
 {
 	int fd = -1;
 	int u;
@@ -220,7 +215,7 @@ open_sbuf()
 
 /* close_sbuf: close scratch file */
 int
-close_sbuf()
+close_sbuf(void)
 {
 	if (sfp) {
 		if (fclose(sfp) < 0) {
@@ -238,8 +233,7 @@ close_sbuf()
 
 /* quit: remove_lines scratch file and exit */
 void
-quit(n)
-	int n;
+quit(int n)
 {
 	if (sfp) {
 		fclose(sfp);
@@ -253,7 +247,7 @@ unsigned char ctab[256];		/* character translation table */
 
 /* init_buffers: open scratch buffer; initialize line queue */
 void
-init_buffers()
+init_buffers(void)
 {
 	int i = 0;
 
@@ -278,11 +272,7 @@ init_buffers()
 
 /* translit_text: translate characters in a string */
 char *
-translit_text(s, len, from, to)
-	char *s;
-	int len;
-	int from;
-	int to;
+translit_text(char *s, int len, int from, int to)
 {
 	static int i = 0;
 
diff --git a/bin/ed/cbc.c b/bin/ed/cbc.c
index 24b0385d62d2..9802bd677f52 100644
--- a/bin/ed/cbc.c
+++ b/bin/ed/cbc.c
@@ -102,7 +102,7 @@ int des_n = 0;			/* index for put_des_char/get_des_char */
 
 /* init_des_cipher: initialize DES */
 void
-init_des_cipher()
+init_des_cipher(void)
 {
 #ifdef DES
 	int i;
@@ -121,8 +121,7 @@ init_des_cipher()
 
 /* get_des_char: return next char in an encrypted file */
 int
-get_des_char(fp)
-	FILE *fp;
+get_des_char(FILE *fp)
 {
 #ifdef DES
 	if (des_n >= des_ct) {
@@ -138,9 +137,7 @@ get_des_char(fp)
 
 /* put_des_char: write a char to an encrypted file; return char written */
 int
-put_des_char(c, fp)
-	int c;
-	FILE *fp;
+put_des_char(int c, FILE *fp)
 {
 #ifdef DES
 	if (des_n == sizeof des_buf) {
@@ -156,8 +153,7 @@ put_des_char(c, fp)
 
 /* flush_des_file: flush an encrypted file's output; return status */
 int
-flush_des_file(fp)
-	FILE *fp;
+flush_des_file(FILE *fp)
 {
 #ifdef DES
 	if (des_n == sizeof des_buf) {
@@ -175,7 +171,7 @@ flush_des_file(fp)
  * get keyword from tty or stdin
  */
 int
-get_keyword()
+get_keyword(void)
 {
 	char *p;			/* used to obtain the key */
 	Desbuf msgbuf;			/* I/O buffer */
@@ -202,8 +198,7 @@ get_keyword()
  * print a warning message and, possibly, terminate
  */
 void
-des_error(s)
-	const char *s;		/* the message */
+des_error(const char *s)
 {
 	errmsg = s ? s : strerror(errno);
 }
@@ -212,9 +207,7 @@ des_error(s)
  * map a hex character to an integer
  */
 int
-hex_to_binary(c, radix)
-	int c;			/* char to be converted */
-	int radix;		/* base (2 to 16) */
+hex_to_binary(int c, int radix)
 {
 	switch(c) {
 	case '0':		return(0x0);
@@ -242,11 +235,11 @@ hex_to_binary(c, radix)
 
 /*
  * convert the key to a bit pattern
+ *	obuf		bit pattern
+ *	kbuf		the key itself
  */
 void
-expand_des_key(obuf, kbuf)
-	char *obuf;			/* bit pattern */
-	char *kbuf;			/* the key itself */
+expand_des_key(char *obuf, char *kbuf)
 {
 	int i, j;			/* counter in a for loop */
 	int nbuf[64];			/* used for hex/key translation */
@@ -312,8 +305,7 @@ expand_des_key(obuf, kbuf)
  * DES ignores the low order bit of each character.
  */
 void
-set_des_key(buf)
-	Desbuf buf;				/* key block */
+set_des_key(Desbuf buf)				/* key block */
 {
 	int i, j;				/* counter in a for loop */
 	int par;				/* parity counter */
@@ -342,10 +334,7 @@ set_des_key(buf)
  * This encrypts using the Cipher Block Chaining mode of DES
  */
 int
-cbc_encode(msgbuf, n, fp)
-	char *msgbuf;
-	int n;
-	FILE *fp;
+cbc_encode(char *msgbuf, int n, FILE *fp)
 {
 	int inverse = 0;	/* 0 to encrypt, 1 to decrypt */
 
@@ -379,11 +368,11 @@ cbc_encode(msgbuf, n, fp)
 
 /*
  * This decrypts using the Cipher Block Chaining mode of DES
+ *	msgbuf	I/O buffer
+ *	fp	input file descriptor
  */
 int
-cbc_decode(msgbuf, fp)
-	char *msgbuf;		/* I/O buffer */
-	FILE *fp;			/* input file descriptor */
+cbc_decode(char *msgbuf, FILE *fp)
 {
 	Desbuf tbuf;	/* temp buffer for initialization vector */
 	int n;			/* number of bytes actually read */
diff --git a/bin/ed/ed.h b/bin/ed/ed.h
index ad9c38f0273a..1a03bb1b6ba6 100644
--- a/bin/ed/ed.h
+++ b/bin/ed/ed.h
@@ -175,92 +175,80 @@ if ((i) > (n)) { \
 /* NEWLINE_TO_NUL: overwrite newlines with ASCII NULs */
 #define NEWLINE_TO_NUL(s, l) translit_text(s, l, '\n', '\0')
 
-#ifdef sun
-# define strerror(n) sys_errlist[n]
-#endif
-
-#ifndef __P
-# ifndef __STDC__
-#  define __P(proto) ()
-# else
-#  define __P(proto) proto
-# endif
-#endif
-
 /* Local Function Declarations */
-void add_line_node __P((line_t *));
-int append_lines __P((long));
-int apply_subst_template __P((const char *, regmatch_t *, int, int));
-int build_active_list __P((int));
-int cbc_decode __P((char *, FILE *));
-int cbc_encode __P((char *, int, FILE *));
-int check_addr_range __P((long, long));
-void clear_active_list __P((void));
-void clear_undo_stack __P((void));
-int close_sbuf __P((void));
-int copy_lines __P((long));
-int delete_lines __P((long, long));
-void des_error __P((const char *));
-int display_lines __P((long, long, int));
-line_t *dup_line_node __P((line_t *));
-int exec_command __P((void));
-long exec_global __P((int, int));
-void expand_des_key __P((char *, char *));
-int extract_addr_range __P((void));
-char *extract_pattern __P((int));
-int extract_subst_tail __P((int *, long *));
-char *extract_subst_template __P((void));
-int filter_lines __P((long, long, char *));
-int flush_des_file __P((FILE *));
-line_t *get_addressed_line_node __P((long));
-pattern_t *get_compiled_pattern __P((void));
-int get_des_char __P((FILE *));
-char *get_extended_line __P((int *, int));
-char *get_filename __P((void));
-int get_keyword __P((void));
-long get_line_node_addr __P((line_t *));
-long get_matching_node_addr __P((pattern_t *, int));
-long get_marked_node_addr __P((int));
-char *get_sbuf_line __P((line_t *));
-int get_shell_command __P((void));
-int get_stream_line __P((FILE *));
-int get_tty_line __P((void));
-void handle_hup __P((int));
-void handle_int __P((int));
-void handle_winch __P((int));
-int has_trailing_escape __P((char *, char *));
-int hex_to_binary __P((int, int));
-void init_buffers __P((void));
-void init_des_cipher __P((void));
-int is_legal_filename __P((char *));
-int join_lines __P((long, long));
-int mark_line_node __P((line_t *, int));
-int move_lines __P((long));
-line_t *next_active_node __P((void));
-long next_addr __P((void));
-int open_sbuf __P((void));
-char *parse_char_class __P((char *));
-int pop_undo_stack __P((void));
-undo_t *push_undo_stack __P((int, long, long));
-int put_des_char __P((int, FILE *));
-const char *put_sbuf_line __P((const char *));
-int put_stream_line __P((FILE *, const char *, int));
-int put_tty_line __P((const char *, int, long, int));
-void quit __P((int));
-long read_file __P((char *, long));
-long read_stream __P((FILE *, long));
-int search_and_replace __P((pattern_t *, int, int));
-int set_active_node __P((line_t *));
-void set_des_key __P((char *));
-void signal_hup __P((int));
-void signal_int __P((int));
-char *strip_escapes __P((char *));
-int substitute_matching_text __P((pattern_t *, line_t *, int, int));
-char *translit_text __P((char *, int, int, int));
-void unmark_line_node __P((line_t *));
-void unset_active_nodes __P((line_t *, line_t *));
-long write_file __P((char *, const char *, long, long));
-long write_stream __P((FILE *, long, long));
+void add_line_node(line_t *);
+int append_lines(long);
+int apply_subst_template(const char *, regmatch_t *, int, int);
+int build_active_list(int);
+int cbc_decode(char *, FILE *);
+int cbc_encode(char *, int, FILE *);
+int check_addr_range(long, long);
+void clear_active_list(void);
+void clear_undo_stack(void);
+int close_sbuf(void);
+int copy_lines(long);
+int delete_lines(long, long);
+void des_error(const char *);
+int display_lines(long, long, int);
+line_t *dup_line_node(line_t *);
+int exec_command(void);
+long exec_global(int, int);
+void expand_des_key(char *, char *);
+int extract_addr_range(void);
+char *extract_pattern(int);
+int extract_subst_tail(int *, long *);
+char *extract_subst_template(void);
+int filter_lines(long, long, char *);
+int flush_des_file(FILE *);
+line_t *get_addressed_line_node(long);
+pattern_t *get_compiled_pattern(void);
+int get_des_char(FILE *);
+char *get_extended_line(int *, int);
+char *get_filename(void);
+int get_keyword(void);
+long get_line_node_addr(line_t *);
+long get_matching_node_addr(pattern_t *, int);
+long get_marked_node_addr(int);
+char *get_sbuf_line(line_t *);
+int get_shell_command(void);
+int get_stream_line(FILE *);
+int get_tty_line(void);
+void handle_hup(int);
+void handle_int(int);
+void handle_winch(int);
+int has_trailing_escape(char *, char *);
+int hex_to_binary(int, int);
+void init_buffers(void);
+void init_des_cipher(void);
+int is_legal_filename(char *);
+int join_lines(long, long);
+int mark_line_node(line_t *, int);
+int move_lines(long);
+line_t *next_active_node(void);
+long next_addr(void);
+int open_sbuf(void);
+char *parse_char_class(char *);
+int pop_undo_stack(void);
+undo_t *push_undo_stack(int, long, long);
+int put_des_char(int, FILE *);
+const char *put_sbuf_line(const char *);
+int put_stream_line(FILE *, const char *, int);
+int put_tty_line(const char *, int, long, int);
+void quit(int);
+long read_file(char *, long);
+long read_stream(FILE *, long);
+int search_and_replace(pattern_t *, int, int);
+int set_active_node(line_t *);
+void set_des_key(char *);
+void signal_hup(int);
+void signal_int(int);
+char *strip_escapes(char *);
+int substitute_matching_text(pattern_t *, line_t *, int, int);
+char *translit_text(char *, int, int, int);
+void unmark_line_node(line_t *);
+void unset_active_nodes(line_t *, line_t *);
+long write_file(char *, const char *, long, long);
+long write_stream(FILE *, long, long);
 
 /* global buffers */
 extern char stdinbuf[];
@@ -282,6 +270,3 @@ extern const char *errmsg;
 extern long first_addr;
 extern int lineno;
 extern long second_addr;
-#ifdef sun
-extern char *sys_errlist[];
-#endif
diff --git a/bin/ed/glbl.c b/bin/ed/glbl.c
index 163f170812cf..06c68487d044 100644
--- a/bin/ed/glbl.c
+++ b/bin/ed/glbl.c
@@ -41,8 +41,7 @@ static const char rcsid[] =
 
 /* build_active_list:  add line matching a pattern to the global-active list */
 int
-build_active_list(isgcmd)
-	int isgcmd;
+build_active_list(int isgcmd)
 {
 	pattern_t *pat;
 	line_t *lp;
@@ -75,9 +74,7 @@ build_active_list(isgcmd)
 /* exec_global: apply command list in the command buffer to the active
    lines in a range; return command status */
 long
-exec_global(interact, gflag)
-	int interact;
-	int gflag;
+exec_global(int interact, int gflag)
 {
 	static char *ocmd = NULL;
 	static int ocmdsz = 0;
@@ -149,8 +146,7 @@ long active_ndx;		/* active_list index (modulo active_last) */
 
 /* set_active_node: add a line node to the global-active list */
 int
-set_active_node(lp)
-	line_t *lp;
+set_active_node(line_t *lp)
 {
 	if (active_last + 1 > active_size) {
 		int ti = active_size;
@@ -188,8 +184,7 @@ set_active_node(lp)
 
 /* unset_active_nodes: remove a range of lines from the global-active list */
 void
-unset_active_nodes(np, mp)
-	line_t *np, *mp;
+unset_active_nodes(line_t *np, line_t *mp)
 {
 	line_t *lp;
 	long i;
@@ -206,7 +201,7 @@ unset_active_nodes(np, mp)
 
 /* next_active_node: return the next global-active line node */
 line_t *
-next_active_node()
+next_active_node(void)
 {
 	while (active_ptr < active_last && active_list[active_ptr] == NULL)
 		active_ptr++;
@@ -216,7 +211,7 @@ next_active_node()
 
 /* clear_active_list: clear the global-active list */
 void
-clear_active_list()
+clear_active_list(void)
 {
 	SPL1();
 	active_size = active_last = active_ptr = active_ndx = 0;
diff --git a/bin/ed/io.c b/bin/ed/io.c
index 47d0502bdf51..b0edf24d5b16 100644
--- a/bin/ed/io.c
+++ b/bin/ed/io.c
@@ -37,9 +37,7 @@ extern int scripted;
 
 /* read_file: read a named file/pipe into the buffer; return line count */
 long
-read_file(fn, n)
-	char *fn;
-	long n;
+read_file(char *fn, long n)
 {
 	FILE *fp;
 	long size;
@@ -70,9 +68,7 @@ int newline_added;		/* if set, newline appended to input file */
 
 /* read_stream: read a stream into the editor buffer; return status */
 long
-read_stream(fp, n)
-	FILE *fp;
-	long n;
+read_stream(FILE *fp, long n)
 {
 	line_t *lp = get_addressed_line_node(n);
 	undo_t *up = NULL;
@@ -121,8 +117,7 @@ read_stream(fp, n)
 
 /* get_stream_line: read a line of text from a stream; return line length */
 int
-get_stream_line(fp)
-	FILE *fp;
+get_stream_line(FILE *fp)
 {
 	int c;
 	int i = 0;
@@ -151,11 +146,7 @@ get_stream_line(fp)
 
 /* write_file: write a range of lines to a named file/pipe; return line count */
 long
-write_file(fn, mode, n, m)
-	char *fn;
-	const char *mode;
-	long n;
-	long m;
+write_file(char *fn, const char *mode, long n, long m)
 {
 	FILE *fp;
 	long size;
@@ -179,10 +170,7 @@ write_file(fn, mode, n, m)
 
 /* write_stream: write a range of lines to a stream; return status */
 long
-write_stream(fp, n, m)
-	FILE *fp;
-	long n;
-	long m;
+write_stream(FILE *fp, long n, long m)
 {
 	line_t *lp = get_addressed_line_node(n);
 	unsigned long size = 0;
@@ -211,10 +199,7 @@ write_stream(fp, n, m)
 
 /* put_stream_line: write a line of text to a stream; return status */
 int
-put_stream_line(fp, s, len)
-	FILE *fp;
-	const char *s;
-	int len;
+put_stream_line(FILE *fp, const char *s, int len)
 {
 	while (len--)
 		if ((des ? put_des_char(*s++, fp) : fputc(*s++, fp)) < 0) {
@@ -227,9 +212,7 @@ put_stream_line(fp, s, len)
 
 /* get_extended_line: get a an extended line from stdin */
 char *
-get_extended_line(sizep, nonl)
-	int *sizep;
-	int nonl;
+get_extended_line(int *sizep, int nonl)
 {
 	static char *cvbuf = NULL;		/* buffer */
 	static int cvbufsz = 0;			/* buffer size */
@@ -272,7 +255,7 @@ get_extended_line(sizep, nonl)
 
 /* get_tty_line: read a line of text from stdin; return line length */
 int
-get_tty_line()
+get_tty_line(void)
 {
 	int oi = 0;
 	int i = 0;
@@ -320,11 +303,7 @@ extern int cols;
 
 /* put_tty_line: print text to stdout */
 int
-put_tty_line(s, l, n, gflag)
-	const char *s;
-	int l;
-	long n;
-	int gflag;
+put_tty_line(const char *s, int l, long n, int gflag)
 {
 	int col = 0;
 	int lc = 0;
diff --git a/bin/ed/main.c b/bin/ed/main.c
index 220dbc8a1da4..54a5a3544be4 100644
--- a/bin/ed/main.c
+++ b/bin/ed/main.c
@@ -103,9 +103,7 @@ const char usage[] = "usage: %s [-] [-sx] [-p string] [name]\n";
 
 /* ed: line editor */
 int
-main(argc, argv)
-	int argc;
-	char **argv;
+main(int argc, char *argv[])
 {
 	int c, n;
 	long status = 0;
@@ -266,7 +264,7 @@ long first_addr, second_addr, addr_cnt;
 /* extract_addr_range: get line addresses from the command buffer until an
    illegal address is seen; return status */
 int
-extract_addr_range()
+extract_addr_range(void)
 {
 	long addr;
 
@@ -298,7 +296,7 @@ extract_addr_range()
 
 /*  next_addr: return the next line address in the command buffer */
 long
-next_addr()
+next_addr(void)
 {
 	const char *hd;
 	long addr = current_addr;
@@ -449,7 +447,7 @@ long rows = 22;		/* scroll length: ws_row - 2 */
 /* exec_command: execute the next command in command buffer; return print
    request, if any */
 int
-exec_command()
+exec_command(void)
 {
 	extern long u_current_addr;
 	extern long u_addr_last;
@@ -883,8 +881,7 @@ exec_command()
 
 /* check_addr_range: return status of address range check */
 int
-check_addr_range(n, m)
-	long n, m;
+check_addr_range(long n, long m)
 {
 	if (addr_cnt == 0) {
 		first_addr = n;
@@ -903,9 +900,7 @@ check_addr_range(n, m)
    pattern in a given direction.  wrap around begin/end of editor buffer if
    necessary */
 long
-get_matching_node_addr(pat, dir)
-	pattern_t *pat;
-	int dir;
+get_matching_node_addr(pattern_t *pat, int dir)
 {
 	char *s;
 	long n = current_addr;
@@ -930,7 +925,7 @@ get_matching_node_addr(pat, dir)
 
 /* get_filename: return pointer to copy of filename in the command buffer */
 char *
-get_filename()
+get_filename(void)
 {
 	static char *file = NULL;
 	static int filesz = 0;
@@ -973,7 +968,7 @@ get_filename()
 /* get_shell_command: read a shell command from stdin; return substitution
    status */
 int
-get_shell_command()
+get_shell_command(void)
 {
 	static char *buf = NULL;
 	static int n = 0;
@@ -1039,8 +1034,7 @@ get_shell_command()
 /* append_lines: insert text from stdin to after line n; stop when either a
    single period is read or EOF; return status */
 int
-append_lines(n)
-	long n;
+append_lines(long n)
 {
 	int l;
 	const char *lp = ibuf;
@@ -1089,9 +1083,7 @@ append_lines(n)
 
 /* join_lines: replace a range of lines with the joined text of those lines */
 int
-join_lines(from, to)
-	long from;
-	long to;
+join_lines(long from, long to)
 {
 	static char *buf = NULL;
 	static int n;
@@ -1128,8 +1120,7 @@ join_lines(from, to)
 
 /* move_lines: move a range of lines */
 int
-move_lines(addr)
-	long addr;
+move_lines(long addr)
 {
 	line_t *b1, *a1, *b2, *a2;
 	long n = INC_MOD(second_addr, addr_last);
@@ -1173,8 +1164,7 @@ move_lines(addr)
 
 /* copy_lines: copy a range of lines; return status */
 int
-copy_lines(addr)
-	long addr;
+copy_lines(long addr)
 {
 	line_t *lp, *np = get_addressed_line_node(first_addr);
 	undo_t *up = NULL;
@@ -1210,8 +1200,7 @@ copy_lines(addr)
 
 /* delete_lines: delete a range of lines */
 int
-delete_lines(from, to)
-	long from, to;
+delete_lines(long from, long to)
 {
 	line_t *n, *p;
 
@@ -1236,10 +1225,7 @@ delete_lines(from, to)
 
 /* display_lines: print a range of lines to stdout */
 int
-display_lines(from, to, gflag)
-	long from;
-	long to;
-	int gflag;
+display_lines(long from, long to, int gflag)
 {
 	line_t *bp;
 	line_t *ep;
@@ -1268,9 +1254,7 @@ int markno;				/* line marker count */
 
 /* mark_line_node: set a line node mark */
 int
-mark_line_node(lp, n)
-	line_t *lp;
-	int n;
+mark_line_node(line_t *lp, int n)
 {
 	if (!islower((unsigned char)n)) {
 		errmsg = "invalid mark character";
@@ -1284,8 +1268,7 @@ mark_line_node(lp, n)
 
 /* get_marked_node_addr: return address of a marked line */
 long
-get_marked_node_addr(n)
-	int n;
+get_marked_node_addr(int n)
 {
 	if (!islower((unsigned char)n)) {
 		errmsg = "invalid mark character";
@@ -1297,8 +1280,7 @@ get_marked_node_addr(n)
 
 /* unmark_line_node: clear line node mark */
 void
-unmark_line_node(lp)
-	line_t *lp;
+unmark_line_node(line_t *lp)
 {
 	int i;
 
@@ -1312,8 +1294,7 @@ unmark_line_node(lp)
 
 /* dup_line_node: return a pointer to a copy of a line node */
 line_t *
-dup_line_node(lp)
-	line_t *lp;
+dup_line_node(line_t *lp)
 {
 	line_t *np;
 
@@ -1331,9 +1312,7 @@ dup_line_node(lp)
 /* has_trailing_escape:  return the parity of escapes preceding a character
    in a string */
 int
-has_trailing_escape(s, t)
-	char *s;
-	char *t;
+has_trailing_escape(char *s, char *t)
 {
     return (s == t || *(t - 1) != '\\') ? 0 : !has_trailing_escape(s, t - 1);
 }
@@ -1341,8 +1320,7 @@ has_trailing_escape(s, t)
 
 /* strip_escapes: return copy of escaped string of at most length PATH_MAX */
 char *
-strip_escapes(s)
-	char *s;
+strip_escapes(char *s)
 {
 	static char *file = NULL;
 	static int filesz = 0;
@@ -1358,8 +1336,7 @@ strip_escapes(s)
 
 
 void
-signal_hup(signo)
-	int signo;
+signal_hup(int signo)
 {
 	if (mutex)
 		sigflags |= (1 << (signo - 1));
@@ -1369,8 +1346,7 @@ signal_hup(signo)
 
 
 void
-signal_int(signo)
-	int signo;
+signal_int(int signo)
 {
 	if (mutex)
 		sigflags |= (1 << (signo - 1));
@@ -1380,8 +1356,7 @@ signal_int(signo)
 
 
 void
-handle_hup(signo)
-	int signo;
+handle_hup(int signo)
 {
 	char *hup = NULL;		/* hup filename */
 	char *s;
@@ -1406,8 +1381,7 @@ handle_hup(signo)
 
 
 void
-handle_int(signo)
-	int signo;
+handle_int(int signo)
 {
 	if (!sigactive)
 		quit(1);
@@ -1423,8 +1397,7 @@ handle_int(signo)
 int cols = 72;				/* wrap column */
 
 void
-handle_winch(signo)
-	int signo;
+handle_winch(int signo)
 {
 	int save_errno = errno;
 
@@ -1441,8 +1414,7 @@ handle_winch(signo)
 
 /* is_legal_filename: return a legal filename */
 int
-is_legal_filename(s)
-	char *s;
+is_legal_filename(char *s)
 {
 	if (red && (*s == '!' || !strcmp(s, "..") || strchr(s, '/'))) {
 		errmsg = "shell access restricted";
diff --git a/bin/ed/re.c b/bin/ed/re.c
index 52dacdcf6244..5cd43fa21db8 100644
--- a/bin/ed/re.c
+++ b/bin/ed/re.c
@@ -41,7 +41,7 @@ const char *errmsg = "";
 /* get_compiled_pattern: return pointer to compiled pattern from command
    buffer */
 pattern_t *
-get_compiled_pattern()
+get_compiled_pattern(void)
 {
 	static pattern_t *exp = NULL;
 	static char error[1024];
@@ -81,8 +81,7 @@ get_compiled_pattern()
 /* extract_pattern: copy a pattern string from the command buffer; return
    pointer to the copy */
 char *
-extract_pattern(delimiter)
-	int delimiter;
+extract_pattern(int delimiter)
 {
 	static char *lhbuf = NULL;	/* buffer */
 	static int lhbufsz = 0;		/* buffer size */
@@ -118,8 +117,7 @@ extract_pattern(delimiter)
 
 /* parse_char_class: expand a POSIX character class */
 char *
-parse_char_class(s)
-	char *s;
+parse_char_class(char *s)
 {
 	int c, d;
 
diff --git a/bin/ed/sub.c b/bin/ed/sub.c
index 1d538486a767..b8d215b41b65 100644
--- a/bin/ed/sub.c
+++ b/bin/ed/sub.c
@@ -40,9 +40,7 @@ int rhbufi;			/* rhs substitution buffer index */
 
 /* extract_subst_tail: extract substitution tail from the command buffer */
 int
-extract_subst_tail(flagp, np)
-	int *flagp;
-	long *np;
+extract_subst_tail(int *flagp, long *np)
 {
 	char delimiter;
 
@@ -73,7 +71,7 @@ extract_subst_tail(flagp, np)
 /* extract_subst_template: return pointer to copy of substitution template
    in the command buffer */
 char *
-extract_subst_template()
+extract_subst_template(void)
 {
 	int n = 0;
 	int i = 0;
@@ -115,10 +113,7 @@ int rbufsz;			/* substitute_matching_text buffer size */
 /* search_and_replace: for each line in a range, change text matching a pattern
    according to a substitution template; return status  */
 int
-search_and_replace(pat, gflag, kth)
-	pattern_t *pat;
-	int gflag;
-	int kth;
+search_and_replace(pattern_t *pat, int gflag, int kth)
 {
 	undo_t *up;
 	const char *txt;
@@ -172,11 +167,7 @@ search_and_replace(pat, gflag, kth)
 /* substitute_matching_text: replace text matched by a pattern according to
    a substitution template; return pointer to the modified text */
 int
-substitute_matching_text(pat, lp, gflag, kth)
-	pattern_t *pat;
-	line_t *lp;
-	int gflag;
-	int kth;
+substitute_matching_text(pattern_t *pat, line_t *lp, int gflag, int kth)
 {
 	int off = 0;
 	int changed = 0;
@@ -234,11 +225,7 @@ substitute_matching_text(pat, lp, gflag, kth)
 /* apply_subst_template: modify text according to a substitution template;
    return offset to end of modified text */
 int
-apply_subst_template(boln, rm, off, re_nsub)
-	const char *boln;
-	regmatch_t *rm;
-	int off;
-	int re_nsub;
+apply_subst_template(const char *boln, regmatch_t *rm, int off, int re_nsub)
 {
 	int j = 0;
 	int k = 0;
diff --git a/bin/ed/undo.c b/bin/ed/undo.c
index 8feb38187e0f..73d488c9d5f0 100644
--- a/bin/ed/undo.c
+++ b/bin/ed/undo.c
@@ -40,10 +40,7 @@ long u_p = 0;					/* undo stack pointer */
 
 /* push_undo_stack: return pointer to initialized undo node */
 undo_t *
-push_undo_stack(type, from, to)
-	int type;
-	long from;
-	long to;
+push_undo_stack(int type, long from, long to)
 {
 	undo_t *t;
 
@@ -87,7 +84,7 @@ long u_addr_last = -1;		/* if >= 0, undo enabled */
 
 /* pop_undo_stack: undo last change to the editor buffer */
 int
-pop_undo_stack()
+pop_undo_stack(void)
 {
 	long n;
 	long o_current_addr = current_addr;
@@ -136,7 +133,7 @@ pop_undo_stack()
 
 /* clear_undo_stack: clear the undo stack */
 void
-clear_undo_stack()
+clear_undo_stack(void)
 {
 	line_t *lp, *ep, *tl;
 
diff --git a/bin/expr/expr.y b/bin/expr/expr.y
index 5367b89fdee4..d368ce3008d7 100644
--- a/bin/expr/expr.y
+++ b/bin/expr/expr.y
@@ -32,35 +32,34 @@ struct val {
 
 struct val *result;
 
-int		chk_div __P((quad_t, quad_t));
-int		chk_minus __P((quad_t, quad_t, quad_t));
-int		chk_plus __P((quad_t, quad_t, quad_t));
-int		chk_times __P((quad_t, quad_t, quad_t));
-void		free_value __P((struct val *));
-int		is_zero_or_null __P((struct val *));
-int		isstring __P((struct val *));
-int		main __P((int, char **));
-struct val	*make_integer __P((quad_t));
-struct val	*make_str __P((const char *));
-struct val	*op_and __P((struct val *, struct val *));
-struct val	*op_colon __P((struct val *, struct val *));
-struct val	*op_div __P((struct val *, struct val *));
-struct val	*op_eq __P((struct val *, struct val *));
-struct val	*op_ge __P((struct val *, struct val *));
-struct val	*op_gt __P((struct val *, struct val *));
-struct val	*op_le __P((struct val *, struct val *));
-struct val	*op_lt __P((struct val *, struct val *));
-struct val	*op_minus __P((struct val *, struct val *));
-struct val	*op_ne __P((struct val *, struct val *));
-struct val	*op_or __P((struct val *, struct val *));
-struct val	*op_plus __P((struct val *, struct val *));
-struct val	*op_rem __P((struct val *, struct val *));
-struct val	*op_times __P((struct val *, struct val *));
-quad_t		to_integer __P((struct val *));
-void		to_string __P((struct val *));
-int		yyerror __P((const char *));
-int		yylex __P((void));
-int		yyparse __P((void));
+int		chk_div(quad_t, quad_t);
+int		chk_minus(quad_t, quad_t, quad_t);
+int		chk_plus(quad_t, quad_t, quad_t);
+int		chk_times(quad_t, quad_t, quad_t);
+void		free_value(struct val *);
+int		is_zero_or_null(struct val *);
+int		isstring(struct val *);
+struct val	*make_integer(quad_t);
+struct val	*make_str(const char *);
+struct val	*op_and(struct val *, struct val *);
+struct val	*op_colon(struct val *, struct val *);
+struct val	*op_div(struct val *, struct val *);
+struct val	*op_eq(struct val *, struct val *);
+struct val	*op_ge(struct val *, struct val *);
+struct val	*op_gt(struct val *, struct val *);
+struct val	*op_le(struct val *, struct val *);
+struct val	*op_lt(struct val *, struct val *);
+struct val	*op_minus(struct val *, struct val *);
+struct val	*op_ne(struct val *, struct val *);
+struct val	*op_or(struct val *, struct val *);
+struct val	*op_plus(struct val *, struct val *);
+struct val	*op_rem(struct val *, struct val *);
+struct val	*op_times(struct val *, struct val *);
+quad_t		to_integer(struct val *);
+void		to_string(struct val *);
+int		yyerror(const char *);
+int		yylex(void);
+int		yyparse(void);
 
 char **av;
 %}
@@ -106,8 +105,7 @@ expr:	TOKEN
 %%
 
 struct val *
-make_integer (i)
-quad_t i;
+make_integer(quad_t i)
 {
 	struct val *vp;
 
@@ -122,8 +120,7 @@ quad_t i;
 }
 
 struct val *
-make_str (s)
-const char *s;
+make_str(const char *s)
 {
 	struct val *vp;
 	size_t i;
@@ -152,8 +149,7 @@ const char *s;
 
 
 void
-free_value (vp)
-struct val *vp;
+free_value(struct val *vp)
 {
 	if (vp->type == string || vp->type == numeric_string)
 		free (vp->u.s);	
@@ -161,8 +157,7 @@ struct val *vp;
 
 
 quad_t
-to_integer (vp)
-struct val *vp;
+to_integer(struct val *vp)
 {
 	quad_t i;
 
@@ -185,8 +180,7 @@ struct val *vp;
 }
 
 void
-to_string (vp)
-struct val *vp;
+to_string(struct val *vp)
 {
 	char *tmp;
 
@@ -205,8 +199,7 @@ struct val *vp;
 
 
 int
-isstring (vp)
-struct val *vp;
+isstring(struct val *vp)
 {
 	/* only TRUE if this string is not a valid integer */
 	return (vp->type == string);
@@ -214,7 +207,7 @@ struct val *vp;
 
 
 int
-yylex ()
+yylex(void)
 {
 	char *p;
 
@@ -239,8 +232,7 @@ yylex ()
 }
 
 int
-is_zero_or_null (vp)
-struct val *vp;
+is_zero_or_null(struct val *vp)
 {
 	if (vp->type == integer) {
 		return (vp->u.i == 0);
@@ -251,9 +243,7 @@ struct val *vp;
 }
 
 int
-main (argc, argv)
-int argc __unused;
-char **argv;
+main(int argc __unused, char *argv[])
 {
 	setlocale (LC_ALL, "");
 
@@ -270,16 +260,14 @@ char **argv;
 }
 
 int
-yyerror (s)
-const char *s __unused;
+yyerror(const char *s __unused)
 {
 	errx (2, "syntax error");
 }
 
 
 struct val *
-op_or (a, b)
-struct val *a, *b;
+op_or(struct val *a, struct val *b)
 {
 	if (is_zero_or_null (a)) {
 		free_value (a);
@@ -291,8 +279,7 @@ struct val *a, *b;
 }
 		
 struct val *
-op_and (a, b)
-struct val *a, *b;
+op_and(struct val *a, struct val *b)
 {
 	if (is_zero_or_null (a) || is_zero_or_null (b)) {
 		free_value (a);
@@ -305,8 +292,7 @@ struct val *a, *b;
 }
 
 struct val *
-op_eq (a, b)
-struct val *a, *b;
+op_eq(struct val *a, struct val *b)
 {
 	struct val *r; 
 
@@ -326,8 +312,7 @@ struct val *a, *b;
 }
 
 struct val *
-op_gt (a, b)
-struct val *a, *b;
+op_gt(struct val *a, struct val *b)
 {
 	struct val *r;
 
@@ -347,8 +332,7 @@ struct val *a, *b;
 }
 
 struct val *
-op_lt (a, b)
-struct val *a, *b;
+op_lt(struct val *a, struct val *b)
 {
 	struct val *r;
 
@@ -368,8 +352,7 @@ struct val *a, *b;
 }
 
 struct val *
-op_ge (a, b)
-struct val *a, *b;
+op_ge(struct val *a, struct val *b)
 {
 	struct val *r;
 
@@ -389,8 +372,7 @@ struct val *a, *b;
 }
 
 struct val *
-op_le (a, b)
-struct val *a, *b;
+op_le(struct val *a, struct val *b)
 {
 	struct val *r;
 
@@ -410,8 +392,7 @@ struct val *a, *b;
 }
 
 struct val *
-op_ne (a, b)
-struct val *a, *b;
+op_ne(struct val *a, struct val *b)
 {
 	struct val *r;
 
@@ -431,8 +412,7 @@ struct val *a, *b;
 }
 
 int
-chk_plus (a, b, r)
-quad_t a, b, r;
+chk_plus(quad_t a, quad_t b, quad_t r)
 {
 	/* sum of two positive numbers must be positive */
 	if (a > 0 && b > 0 && r <= 0)
@@ -445,8 +425,7 @@ quad_t a, b, r;
 }
 
 struct val *
-op_plus (a, b)
-struct val *a, *b;
+op_plus(struct val *a, struct val *b)
 {
 	struct val *r;
 
@@ -464,8 +443,7 @@ struct val *a, *b;
 }
 
 int
-chk_minus (a, b, r)
-quad_t a, b, r;
+chk_minus(quad_t a, quad_t b, quad_t r)
 {
 	/* special case subtraction of QUAD_MIN */
 	if (b == QUAD_MIN) {
@@ -479,8 +457,7 @@ quad_t a, b, r;
 }
 
 struct val *
-op_minus (a, b)
-struct val *a, *b;
+op_minus(struct val *a, struct val *b)
 {
 	struct val *r;
 
@@ -498,8 +475,7 @@ struct val *a, *b;
 }
 
 int
-chk_times (a, b, r)
-quad_t a, b, r;
+chk_times(quad_t a, quad_t b, quad_t r)
 {
 	/* special case: first operand is 0, no overflow possible */
 	if (a == 0)
@@ -511,8 +487,7 @@ quad_t a, b, r;
 }
 
 struct val *
-op_times (a, b)
-struct val *a, *b;
+op_times(struct val *a, struct val *b)
 {
 	struct val *r;
 
@@ -530,8 +505,7 @@ struct val *a, *b;
 }
 
 int
-chk_div (a, b)
-quad_t a, b;
+chk_div(quad_t a, quad_t b)
 {
 	/* div by zero has been taken care of before */
 	/* only QUAD_MIN / -1 causes overflow */
@@ -542,8 +516,7 @@ quad_t a, b;
 }
 
 struct val *
-op_div (a, b)
-struct val *a, *b;
+op_div(struct val *a, struct val *b)
 {
 	struct val *r;
 
@@ -565,8 +538,7 @@ struct val *a, *b;
 }
 	
 struct val *
-op_rem (a, b)
-struct val *a, *b;
+op_rem(struct val *a, struct val *b)
 {
 	struct val *r;
 
@@ -586,8 +558,7 @@ struct val *a, *b;
 }
 	
 struct val *
-op_colon (a, b)
-struct val *a, *b;
+op_colon(struct val *a, struct val *b)
 {
 	regex_t rp;
 	regmatch_t rm[2];