fix: comment out main, so there is only one main signature.

dwm.c also has a main function defined.

.gitignore

@@ -0,0 +1,20 @@
+# Ignore dotfiles by default
+.*
+
+# Ignore common (generated) file types
+*.a
+*.o
+*.d
+*.so
+*.out
+*.hex
+*.gz
+
+# Ignore specific project files
+compile_commands.json
+/bin/
+/config.mk
+
+# Unignore specific files.
+!.gitignore
+!.clang-format

COPYING

@@ -1,5 +1,6 @@
 MIT/X Consortium License
 
+© 2010-2026 Hiltjo Posthuma <hiltjo@codemadness.org>
 © 2006-2019 Anselm R Garbe <anselm@garbe.ca>
 © 2006-2009 Jukka Salmi <jukka at salmi dot ch>
 © 2006-2007 Sander van Dijk <a dot h dot vandijk at gmail dot com>
@@ -11,7 +12,6 @@ MIT/X Consortium License
 © 2008 Martin Hurton <martin dot hurton at gmail dot com>
 © 2008 Neale Pickett <neale dot woozle dot org>
 © 2009 Mate Nagy <mnagy at port70 dot net>
-© 2010-2016 Hiltjo Posthuma <hiltjo@codemadness.org>
 © 2010-2012 Connor Lane Smith <cls@lubutu.com>
 © 2011 Christoph Lohmann <20h@r-36.net>
 © 2015-2016 Quentin Rameau <quinq@fifth.space>

Makefile

@@ -1,45 +1,92 @@
 # dwm - dynamic window manager
 # See LICENSE file for copyright and license details.
 
-include config.mk
+-include config.mk
 
-SRC = drw.c dwm.c util.c
+VERSION = 6.7
-OBJ = ${SRC:.c=.o}
 
-all: dwm
+INSTALL ?= install
+GZIP    ?= gzip
+TAR     ?= tar
 
-.c.o:
+CFLAGS   := -Os $(CFLAGS) -g -std=gnu99\
-	${CC} -c ${CFLAGS} $<
+	    -Wall -Wextra -Wpedantic -Wno-pointer-arith
+CPPFLAGS := -DNDEBUG $(CPPFLAGS)\
+	    -DVERSION=\"$(VERSION)\" -D_DEFAULT_SOURCE -D_XOPEN_SOURCE=700L -DXINERAMA
+LDFLAGS  := -flto $(LDFLAGS)
+LDLIBS   := $(LDLIBS) -lm
 
-${OBJ}: config.h config.mk
+# Use pkg-config to locate dependencies, and set the correct flags.
+ifeq (,$(shell command -v pkg-config))
+$(error Failed to locate pkg-config, please make sure it is installed or acessible through PATH.)
+else
+CPPFLAGS += $(shell pkg-config --cflags-only-I fontconfig freetype2 x11 xft xinerama)
+LDFLAGS  += $(shell pkg-config --libs-only-L   fontconfig freetype2 x11 xft xinerama)
+LDLIBS   += $(shell pkg-config --libs-only-l   fontconfig freetype2 x11 xft xinerama)
+endif
 
-config.h:
+SRC := $(wildcard src/*.c)
-	cp config.def.h $@
+OBJ := $(addsuffix .o,$(SRC))
+DEP := $(addsuffix .d,$(SRC))
 
-dwm: ${OBJ}
+# Set Q to @ to silence commands being printed, unless --no-silent has been set
-	${CC} -o $@ ${OBJ} ${LDFLAGS}
+ifeq (0, $(words $(findstring --no-silent,$(MAKEFLAGS))))
+Q=@
+endif
 
-clean:
+msg = @printf '%-8s %s\n' "$(1)" "$(2)"
-	rm -f dwm ${OBJ} dwm-${VERSION}.tar.gz
 
-dist: clean
+.PHONY:
-	mkdir -p dwm-${VERSION}
+all: bin/dwm
-	cp -R LICENSE Makefile README config.def.h config.mk\
-		dwm.1 drw.h util.h ${SRC} dwm.png transient.c dwm-${VERSION}
-	tar -cf dwm-${VERSION}.tar dwm-${VERSION}
-	gzip dwm-${VERSION}.tar
-	rm -rf dwm-${VERSION}
 
-install: all
+.PHONY:
-	mkdir -p ${DESTDIR}${PREFIX}/bin
+install: $(DESTDIR)/bin/dwm $(DESTDIR)/share/man/man1/dwm.1.gz
-	cp -f dwm ${DESTDIR}${PREFIX}/bin
+$(DESTDIR)/bin/%: bin/%
-	chmod 755 ${DESTDIR}${PREFIX}/bin/dwm
+	$(call msg,INSTALL,$@)
-	mkdir -p ${DESTDIR}${MANPREFIX}/man1
+	$(Q)$(INSTALL) -D -m0755 $< $@
-	sed "s/VERSION/${VERSION}/g" < dwm.1 > ${DESTDIR}${MANPREFIX}/man1/dwm.1
-	chmod 644 ${DESTDIR}${MANPREFIX}/man1/dwm.1
 
+$(DESTDIR)/share/man/%: man/%
+	$(call msg,INSTALL,$@)
+	$(Q)$(INSTALL) -D -m0644 $< $@
+
+.PHONY:
 uninstall:
-	rm -f ${DESTDIR}${PREFIX}/bin/dwm\
+	$(Q)$(RM) $(DESTDIR)/bin/dwm\
-		${DESTDIR}${MANPREFIX}/man1/dwm.1
+		$(DESTDIR)/share/man/man1/dwm.1.gz
 
-.PHONY: all clean dist install uninstall
+.PHONY:
+clean:
+	$(call msg,CLEAN,src/)
+	$(Q)$(RM) $(OBJ)
+	$(call msg,CLEAN,man/)
+	$(Q)$(RM) $(MAN)
+	$(call msg,CLEAN,bin/)
+	$(Q)$(RM) -r bin/
+
+# Links together the object files into the final binary.
+bin/dwm: $(OBJ) | bin/
+	$(call msg,LD,$@)
+	$(Q)$(CC) $(LDFLAGS) $(LDLIBS) -o $@ $^
+
+# Compiles C sources into Object files
+%.c.o: %.c
+	$(call msg,CC,$@)
+	$(Q)$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+# Compress files requested for compression using GZIP
+%.gz: %
+	$(call msg,GZIP,$@)
+	$(Q)$(GZIP) -k $<
+
+# Create directories
+%/:
+	$(call msg-mkdir,$@)
+	$(Q)mkdir $@
+
+# Generate and include dependencies,
+# ignoring any errors that may occur when doing so.
+%.c.d: %.c
+	$(Q)$(CC) -MM $(CPPFLAGS) -MF $@ $<
+ifeq (0, $(words $(findstring $(MAKECMDGOALS), clean)))
+-include $(DEP)
+endif

config.mk

@@ -1,39 +0,0 @@
-# dwm version
-VERSION = 6.5
-
-# Customize below to fit your system
-
-# paths
-PREFIX = /usr/local
-MANPREFIX = ${PREFIX}/share/man
-
-X11INC = /usr/X11R6/include
-X11LIB = /usr/X11R6/lib
-
-# Xinerama, comment if you don't want it
-XINERAMALIBS  = -lXinerama
-XINERAMAFLAGS = -DXINERAMA
-
-# freetype
-FREETYPELIBS = -lfontconfig -lXft
-FREETYPEINC = /usr/include/freetype2
-# OpenBSD (uncomment)
-#FREETYPEINC = ${X11INC}/freetype2
-#MANPREFIX = ${PREFIX}/man
-
-# includes and libs
-INCS = -I${X11INC} -I${FREETYPEINC}
-LIBS = -L${X11LIB} -lX11 ${XINERAMALIBS} ${FREETYPELIBS}
-
-# flags
-CPPFLAGS = -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_XOPEN_SOURCE=700L -DVERSION=\"${VERSION}\" ${XINERAMAFLAGS}
-#CFLAGS   = -g -std=c99 -pedantic -Wall -O0 ${INCS} ${CPPFLAGS}
-CFLAGS   = -std=c99 -pedantic -Wall -Wno-deprecated-declarations -Os ${INCS} ${CPPFLAGS}
-LDFLAGS  = ${LIBS}
-
-# Solaris
-#CFLAGS = -fast ${INCS} -DVERSION=\"${VERSION}\"
-#LDFLAGS = ${LIBS}
-
-# compiler and linker
-CC = cc

src/config.h

@@ -36,6 +36,7 @@ static const float mfact     = 0.55; /* factor of master area size [0.05..0.95]
 static const int nmaster     = 1;    /* number of clients in master area */
 static const int resizehints = 1;    /* 1 means respect size hints in tiled resizals */
 static const int lockfullscreen = 1; /* 1 will force focus on the fullscreen window */
+static const int refreshrate = 120;  /* refresh rate (per second) for client move/resize */
 
 static const Layout layouts[] = {
 	/* symbol     arrange function */

src/drw.c

@@ -9,54 +9,40 @@
 #include "util.h"
 
 #define UTF_INVALID 0xFFFD
-#define UTF_SIZ     4
 
-static const unsigned char utfbyte[UTF_SIZ + 1] = {0x80,    0, 0xC0, 0xE0, 0xF0};
+static int
-static const unsigned char utfmask[UTF_SIZ + 1] = {0xC0, 0x80, 0xE0, 0xF0, 0xF8};
+utf8decode(const char *s_in, long *u, int *err)
-static const long utfmin[UTF_SIZ + 1] = {       0,    0,  0x80,  0x800,  0x10000};
-static const long utfmax[UTF_SIZ + 1] = {0x10FFFF, 0x7F, 0x7FF, 0xFFFF, 0x10FFFF};
-
-static long
-utf8decodebyte(const char c, size_t *i)
 {
-	for (*i = 0; *i < (UTF_SIZ + 1); ++(*i))
+	static const unsigned char lens[] = {
-		if (((unsigned char)c & utfmask[*i]) == utfbyte[*i])
+		/* 0XXXX */ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
-			return (unsigned char)c & ~utfmask[*i];
+		/* 10XXX */ 0, 0, 0, 0, 0, 0, 0, 0,  /* invalid */
-	return 0;
+		/* 110XX */ 2, 2, 2, 2,
-}
+		/* 1110X */ 3, 3,
-
+		/* 11110 */ 4,
-static size_t
+		/* 11111 */ 0,  /* invalid */
-utf8validate(long *u, size_t i)
+	};
-{
+	static const unsigned char leading_mask[] = { 0x7F, 0x1F, 0x0F, 0x07 };
-	if (!BETWEEN(*u, utfmin[i], utfmax[i]) || BETWEEN(*u, 0xD800, 0xDFFF))
+	static const unsigned int overlong[] = { 0x0, 0x80, 0x0800, 0x10000 };
-		*u = UTF_INVALID;
-	for (i = 1; *u > utfmax[i]; ++i)
-		;
-	return i;
-}
-
-static size_t
-utf8decode(const char *c, long *u, size_t clen)
-{
-	size_t i, j, len, type;
-	long udecoded;
 
+	const unsigned char *s = (const unsigned char *)s_in;
+	int len = lens[*s >> 3];
 	*u = UTF_INVALID;
-	if (!clen)
+	*err = 1;
-		return 0;
+	if (len == 0)
-	udecoded = utf8decodebyte(c[0], &len);
-	if (!BETWEEN(len, 1, UTF_SIZ))
 		return 1;
-	for (i = 1, j = 1; i < clen && j < len; ++i, ++j) {
-		udecoded = (udecoded << 6) | utf8decodebyte(c[i], &type);
-		if (type)
-			return j;
-	}
-	if (j < len)
-		return 0;
-	*u = udecoded;
-	utf8validate(u, len);
 
+	long cp = s[0] & leading_mask[len - 1];
+	for (int i = 1; i < len; ++i) {
+		if (s[i] == '\0' || (s[i] & 0xC0) != 0x80)
+			return i;
+		cp = (cp << 6) | (s[i] & 0x3F);
+	}
+	/* out of range, surrogate, overlong encoding */
+	if (cp > 0x10FFFF || (cp >> 11) == 0x1B || cp < overlong[len - 1])
+		return len;
+
+	*err = 0;
+	*u = cp;
 	return len;
 }
 
@@ -192,8 +178,7 @@ drw_clr_create(Drw *drw, Clr *dest, const char *clrname)
 		die("error, cannot allocate color '%s'", clrname);
 }
 
-/* Wrapper to create color schemes. The caller has to call free(3) on the
+/* Create color schemes. */
- * returned color scheme when done using it. */
 Clr *
 drw_scm_create(Drw *drw, const char *clrnames[], size_t clrcount)
 {
@@ -201,7 +186,7 @@ drw_scm_create(Drw *drw, const char *clrnames[], size_t clrcount)
 	Clr *ret;
 
 	/* need at least two colors for a scheme */
-	if (!drw || !clrnames || clrcount < 2 || !(ret = ecalloc(clrcount, sizeof(XftColor))))
+	if (!drw || !clrnames || clrcount < 2 || !(ret = ecalloc(clrcount, sizeof(Clr))))
 		return NULL;
 
 	for (i = 0; i < clrcount; i++)
@@ -209,6 +194,30 @@ drw_scm_create(Drw *drw, const char *clrnames[], size_t clrcount)
 	return ret;
 }
 
+void
+drw_clr_free(Drw *drw, Clr *c)
+{
+	if (!drw || !c)
+		return;
+
+	/* c is typedef XftColor Clr */
+	XftColorFree(drw->dpy, DefaultVisual(drw->dpy, drw->screen),
+	             DefaultColormap(drw->dpy, drw->screen), c);
+}
+
+void
+drw_scm_free(Drw *drw, Clr *scm, size_t clrcount)
+{
+	size_t i;
+
+	if (!drw || !scm)
+		return;
+
+	for (i = 0; i < clrcount; i++)
+		drw_clr_free(drw, &scm[i]);
+	free(scm);
+}
+
 void
 drw_setfontset(Drw *drw, Fnt *set)
 {
@@ -238,11 +247,11 @@ drw_rect(Drw *drw, int x, int y, unsigned int w, unsigned int h, int filled, int
 int
 drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lpad, const char *text, int invert)
 {
-	int i, ty, ellipsis_x = 0;
+	int ty, ellipsis_x = 0;
-	unsigned int tmpw, ew, ellipsis_w = 0, ellipsis_len;
+	unsigned int tmpw, ew, ellipsis_w = 0, ellipsis_len, hash, h0, h1;
 	XftDraw *d = NULL;
 	Fnt *usedfont, *curfont, *nextfont;
-	int utf8strlen, utf8charlen, render = x || y || w || h;
+	int utf8strlen, utf8charlen, utf8err, render = x || y || w || h;
 	long utf8codepoint = 0;
 	const char *utf8str;
 	FcCharSet *fccharset;
@@ -251,9 +260,8 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lp
 	XftResult result;
 	int charexists = 0, overflow = 0;
 	/* keep track of a couple codepoints for which we have no match. */
-	enum { nomatches_len = 64 };
+	static unsigned int nomatches[128], ellipsis_width, invalid_width;
-	static struct { long codepoint[nomatches_len]; unsigned int idx; } nomatches;
+	static const char invalid[] = "<EFBFBD>";
-	static unsigned int ellipsis_width = 0;
 
 	if (!drw || (render && (!drw->scheme || !w)) || !text || !drw->fonts)
 		return 0;
@@ -263,6 +271,8 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lp
 	} else {
 		XSetForeground(drw->dpy, drw->gc, drw->scheme[invert ? ColFg : ColBg].pixel);
 		XFillRectangle(drw->dpy, drw->drawable, drw->gc, x, y, w, h);
+		if (w < lpad)
+			return x + w;
 		d = XftDrawCreate(drw->dpy, drw->drawable,
 		                  DefaultVisual(drw->dpy, drw->screen),
 		                  DefaultColormap(drw->dpy, drw->screen));
@@ -273,12 +283,14 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lp
 	usedfont = drw->fonts;
 	if (!ellipsis_width && render)
 		ellipsis_width = drw_fontset_getwidth(drw, "...");
+	if (!invalid_width && render)
+		invalid_width = drw_fontset_getwidth(drw, invalid);
 	while (1) {
-		ew = ellipsis_len = utf8strlen = 0;
+		ew = ellipsis_len = utf8err = utf8charlen = utf8strlen = 0;
 		utf8str = text;
 		nextfont = NULL;
 		while (*text) {
-			utf8charlen = utf8decode(text, &utf8codepoint, UTF_SIZ);
+			utf8charlen = utf8decode(text, &utf8codepoint, &utf8err);
 			for (curfont = drw->fonts; curfont; curfont = curfont->next) {
 				charexists = charexists || XftCharExists(drw->dpy, curfont->xfont, utf8codepoint);
 				if (charexists) {
@@ -300,9 +312,9 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lp
 						else
 							utf8strlen = ellipsis_len;
 					} else if (curfont == usedfont) {
-						utf8strlen += utf8charlen;
 						text += utf8charlen;
-						ew += tmpw;
+						utf8strlen += utf8err ? 0 : utf8charlen;
+						ew += utf8err ? 0 : tmpw;
 					} else {
 						nextfont = curfont;
 					}
@@ -310,7 +322,7 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lp
 				}
 			}
 
-			if (overflow || !charexists || nextfont)
+			if (overflow || !charexists || nextfont || utf8err)
 				break;
 			else
 				charexists = 0;
@@ -325,6 +337,12 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lp
 			x += ew;
 			w -= ew;
 		}
+		if (utf8err && (!render || invalid_width < w)) {
+			if (render)
+				drw_text(drw, x, y, w, h, 0, invalid, invert);
+			x += invalid_width;
+			w -= invalid_width;
+		}
 		if (render && overflow)
 			drw_text(drw, ellipsis_x, y, ellipsis_w, h, 0, "...", invert);
 
@@ -338,11 +356,14 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lp
 			 * character must be drawn. */
 			charexists = 1;
 
-			for (i = 0; i < nomatches_len; ++i) {
+			hash = (unsigned int)utf8codepoint;
-				/* avoid calling XftFontMatch if we know we won't find a match */
+			hash = ((hash >> 16) ^ hash) * 0x21F0AAAD;
-				if (utf8codepoint == nomatches.codepoint[i])
+			hash = ((hash >> 15) ^ hash) * 0xD35A2D97;
-					goto no_match;
+			h0 = ((hash >> 15) ^ hash) % LENGTH(nomatches);
-			}
+			h1 = (hash >> 17) % LENGTH(nomatches);
+			/* avoid expensive XftFontMatch call when we know we won't find a match */
+			if (nomatches[h0] == utf8codepoint || nomatches[h1] == utf8codepoint)
+				goto no_match;
 
 			fccharset = FcCharSetCreate();
 			FcCharSetAddChar(fccharset, utf8codepoint);
@@ -371,7 +392,7 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lp
 					curfont->next = usedfont;
 				} else {
 					xfont_free(usedfont);
-					nomatches.codepoint[++nomatches.idx % nomatches_len] = utf8codepoint;
+					nomatches[nomatches[h0] ? h1 : h0] = utf8codepoint;
 no_match:
 					usedfont = drw->fonts;
 				}

src/drw.h

@@ -40,7 +40,9 @@ void drw_font_getexts(Fnt *font, const char *text, unsigned int len, unsigned in
 
 /* Colorscheme abstraction */
 void drw_clr_create(Drw *drw, Clr *dest, const char *clrname);
+void drw_clr_free(Drw *drw, Clr *c);
 Clr *drw_scm_create(Drw *drw, const char *clrnames[], size_t clrcount);
+void drw_scm_free(Drw *drw, Clr *scm, size_t clrcount);
 
 /* Cursor abstraction */
 Cur *drw_cur_create(Drw *drw, int shape);

src/dwm.c

@@ -50,7 +50,6 @@
 #define INTERSECT(x,y,w,h,m)    (MAX(0, MIN((x)+(w),(m)->wx+(m)->ww) - MAX((x),(m)->wx)) \
                                * MAX(0, MIN((y)+(h),(m)->wy+(m)->wh) - MAX((y),(m)->wy)))
 #define ISVISIBLE(C)            ((C->tags & C->mon->tagset[C->mon->seltags]))
-#define LENGTH(X)               (sizeof X / sizeof X[0])
 #define MOUSEMASK               (BUTTONMASK|PointerMotionMask)
 #define WIDTH(X)                ((X)->w + 2 * (X)->bw)
 #define HEIGHT(X)               ((X)->h + 2 * (X)->bw)
@@ -487,7 +486,7 @@ cleanup(void)
 	for (i = 0; i < CurLast; i++)
 		drw_cur_free(drw, cursor[i]);
 	for (i = 0; i < LENGTH(colors); i++)
-		free(scheme[i]);
+		drw_scm_free(drw, scheme[i], 3);
 	free(scheme);
 	XDestroyWindow(dpy, wmcheckwin);
 	drw_free(drw);
@@ -865,13 +864,14 @@ Atom
 getatomprop(Client *c, Atom prop)
 {
 	int di;
-	unsigned long dl;
+	unsigned long nitems, dl;
 	unsigned char *p = NULL;
 	Atom da, atom = None;
 
 	if (XGetWindowProperty(dpy, c->win, prop, 0L, sizeof atom, False, XA_ATOM,
-		&da, &di, &dl, &dl, &p) == Success && p) {
+		&da, &di, &nitems, &dl, &p) == Success && p) {
-		atom = *(Atom *)p;
+		if (nitems > 0)
+			atom = *(Atom *)p;
 		XFree(p);
 	}
 	return atom;
@@ -1172,7 +1172,7 @@ movemouse(const Arg *arg)
 			handler[ev.type](&ev);
 			break;
 		case MotionNotify:
-			if ((ev.xmotion.time - lasttime) <= (1000 / 60))
+			if ((ev.xmotion.time - lasttime) <= (1000 / refreshrate))
 				continue;
 			lasttime = ev.xmotion.time;
 
@@ -1326,7 +1326,7 @@ resizemouse(const Arg *arg)
 			handler[ev.type](&ev);
 			break;
 		case MotionNotify:
-			if ((ev.xmotion.time - lasttime) <= (1000 / 60))
+			if ((ev.xmotion.time - lasttime) <= (1000 / refreshrate))
 				continue;
 			lasttime = ev.xmotion.time;
 
@@ -1851,7 +1851,7 @@ updatebarpos(Monitor *m)
 }
 
 void
-updateclientlist()
+updateclientlist(void)
 {
 	Client *c;
 	Monitor *m;

src/transient.c

@@ -5,6 +5,7 @@
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
 
+/*
 int main(void) {
 	Display *d;
 	Window r, f, t = None;
@@ -40,3 +41,4 @@ int main(void) {
 	XCloseDisplay(d);
 	exit(0);
 }
+*/

src/util.c

@@ -1,4 +1,5 @@
 /* See LICENSE file for copyright and license details. */
+#include <errno.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -10,17 +11,17 @@ void
 die(const char *fmt, ...)
 {
 	va_list ap;
+	int saved_errno;
+
+	saved_errno = errno;
 
 	va_start(ap, fmt);
 	vfprintf(stderr, fmt, ap);
 	va_end(ap);
 
-	if (fmt[0] && fmt[strlen(fmt)-1] == ':') {
+	if (fmt[0] && fmt[strlen(fmt)-1] == ':')
-		fputc(' ', stderr);
+		fprintf(stderr, " %s", strerror(saved_errno));
-		perror(NULL);
+	fputc('\n', stderr);
-	} else {
-		fputc('\n', stderr);
-	}
 
 	exit(1);
 }

src/util.h

@@ -3,6 +3,7 @@
 #define MAX(A, B)               ((A) > (B) ? (A) : (B))
 #define MIN(A, B)               ((A) < (B) ? (A) : (B))
 #define BETWEEN(X, A, B)        ((A) <= (X) && (X) <= (B))
+#define LENGTH(X)               (sizeof (X) / sizeof (X)[0])
 
 void die(const char *fmt, ...);
 void *ecalloc(size_t nmemb, size_t size);