added some comments

client.c

@@ -19,11 +19,11 @@ detachstack(Client *c)
 }
 
 static void
-grabbuttons(Client *c, Bool focus)
+grabbuttons(Client *c, Bool focused)
 {
 	XUngrabButton(dpy, AnyButton, AnyModifier, c->win);
 
-	if(focus) {
+	if(focused) {
 		XGrabButton(dpy, Button1, MODKEY, c->win, False, BUTTONMASK,
 				GrabModeAsync, GrabModeSync, None, None);
 		XGrabButton(dpy, Button1, MODKEY | LockMask, c->win, False, BUTTONMASK,
@@ -304,7 +304,7 @@ resize(Client *c, Bool sizehints, Corner sticky)
 		wc.border_width = 0;
 	else
 		wc.border_width = 1;
-	XConfigureWindow(dpy, c->win, CWX|CWY|CWWidth|CWHeight|CWBorderWidth, &wc);
+	XConfigureWindow(dpy, c->win, CWX | CWY | CWWidth | CWHeight | CWBorderWidth, &wc);
 	XSync(dpy, False);
 }
 

dwm.h

@@ -11,23 +11,19 @@
 #define MOUSEMASK		(BUTTONMASK | PointerMotionMask)
 #define PROTODELWIN		1
 
+enum { NetSupported, NetWMName, NetLast };		/* EWMH atoms */
+enum { WMProtocols, WMDelete, WMLast };			/* default atoms */
+enum { CurNormal, CurResize, CurMove, CurLast };	/* cursor */
+enum { ColFG, ColBG, ColLast };				/* color */
+
+typedef enum {
+	TopLeft, TopRight, BotLeft, BotRight
+} Corner; /* window corners */
+
 typedef union {
 	const char *cmd;
 	int i;
-} Arg;
-
-/* atoms */
-enum { NetSupported, NetWMName, NetLast };
-enum { WMProtocols, WMDelete, WMLast };
-
-/* cursor */
-enum { CurNormal, CurResize, CurMove, CurLast };
-
-/* color */
-enum { ColFG, ColBG, ColLast };
-
-/* window corners */
-typedef enum { TopLeft, TopRight, BotLeft, BotRight } Corner;
+} Arg; /* argument type */
 
 typedef struct {
 	int ascent;
@@ -37,7 +33,7 @@ typedef struct {
 	XFontStruct *xfont;
 } Fnt;
 
-typedef struct { /* draw context */
+typedef struct {
 	int x, y, w, h;
 	unsigned long norm[ColLast];
 	unsigned long sel[ColLast];
@@ -45,7 +41,7 @@ typedef struct { /* draw context */
 	Drawable drawable;
 	Fnt font;
 	GC gc;
-} DC;
+} DC; /* draw context */
 
 typedef struct Client Client;
 struct Client {
@@ -66,77 +62,78 @@ struct Client {
 	Window twin;
 };
 
-extern const char *tags[];
-extern char stext[1024];
-extern int bx, by, bw, bh, bmw, mw, screen, sx, sy, sw, sh;
-extern unsigned int ntags, numlockmask;
-extern void (*handler[LASTEvent])(XEvent *);
-extern void (*arrange)(Arg *);
+extern const char *tags[];			/* all tags */
+extern char stext[1024];			/* status text */
+extern int bx, by, bw, bh, bmw;			/* bar geometry, bar mode label width */
+extern int mw, screen, sx, sy, sw, sh;		/* screen geometry, master width */
+extern unsigned int ntags, numlockmask;		/* number of tags, and dynamic lock mask */
+extern void (*handler[LASTEvent])(XEvent *);	/* event handler */
+extern void (*arrange)(Arg *);			/* arrange function, indicates mode  */
 extern Atom wmatom[WMLast], netatom[NetLast];
-extern Bool running, issel, maximized, *seltag;
-extern Client *clients, *sel, *stack;
+extern Bool running, issel, maximized, *seltag;	/* seltag is array of Bool */
+extern Client *clients, *sel, *stack;		/* Client containers */
 extern Cursor cursor[CurLast];
-extern DC dc;
+extern DC dc;					/* draw context for everything */
 extern Display *dpy;
 extern Window root, barwin;
 
 /* client.c */
-extern void ban(Client *c);
-extern void focus(Client *c);
-extern Client *getclient(Window w);
-extern Client *getctitle(Window w);
-extern void gravitate(Client *c, Bool invert);
-extern void killclient(Arg *arg);
-extern void manage(Window w, XWindowAttributes *wa);
-extern void resize(Client *c, Bool sizehints, Corner sticky);
-extern void setsize(Client *c);
-extern void settitle(Client *c);
-extern void togglemax(Arg *arg);
-extern void unmanage(Client *c);
+extern void ban(Client *c);			/* ban client from screen */
+extern void focus(Client *c);			/* focus c, c may be NULL */
+extern Client *getclient(Window w);		/* return client of w */
+extern Client *getctitle(Window w);		/* return client of title window */
+extern void gravitate(Client *c, Bool invert);	/* gravitate c */
+extern void killclient(Arg *arg);		/* kill c nicely */
+extern void manage(Window w, XWindowAttributes *wa);	/* manage new client */
+extern void resize(Client *c, Bool sizehints, Corner sticky); /* resize c*/
+extern void setsize(Client *c);			/* set the size structs of c */
+extern void settitle(Client *c);		/* set the name of c */
+extern void togglemax(Arg *arg);		/* (un)maximize c */
+extern void unmanage(Client *c);		/* destroy c */
 
 /* draw.c */
-extern void drawall();
-extern void drawstatus();
-extern void drawtitle(Client *c);
-extern unsigned long getcolor(const char *colstr);
-extern void setfont(const char *fontstr);
-extern unsigned int textw(const char *text);
+extern void drawall();				/* draw all visible client titles and the bar */
+extern void drawstatus();			/* draw the bar */
+extern void drawtitle(Client *c);		/* draw title of c */
+extern unsigned long getcolor(const char *colstr);	/* return color of colstr */
+extern void setfont(const char *fontstr);	/* set the font for DC */
+extern unsigned int textw(const char *text);	/* return the text width of text */
 
 /* event.c */
-extern void grabkeys();
-extern void procevent();
+extern void grabkeys();				/* grab all keys defined in config.h */
+extern void procevent();			/* process pending X events */
 
 /* main.c */
-extern int getproto(Window w);
-extern void quit(Arg *arg);
-extern void sendevent(Window w, Atom a, long value);
-extern int xerror(Display *dsply, XErrorEvent *ee);
+extern int getproto(Window w);			/* return protocol mask of WMProtocols property of w */
+extern void quit(Arg *arg);			/* quit dwm nicely */
+extern void sendevent(Window w, Atom a, long value);	/* send synthetic event to w */
+extern int xerror(Display *dsply, XErrorEvent *ee);	/* dwm's X error handler */
 
 /* tag.c */
-extern void initrregs();
-extern Client *getnext(Client *c);
-extern Client *getprev(Client *c);
-extern void settags(Client *c, Client *trans);
-extern void tag(Arg *arg);
-extern void toggletag(Arg *arg);
+extern void initrregs();			/* initialize regexps of rules defined in config.h */
+extern Client *getnext(Client *c);		/* returns next visible client */
+extern Client *getprev(Client *c);		/* returns previous visible client */
+extern void settags(Client *c, Client *trans);	/* updates tags of c */
+extern void tag(Arg *arg);			/* tags c accordingly to arg's index */
+extern void toggletag(Arg *arg);		/* toggles c tags accordingly to arg's index */
 
 /* util.c */
-extern void *emallocz(unsigned int size);
-extern void eprint(const char *errstr, ...);
-extern void *erealloc(void *ptr, unsigned int size);
-extern void spawn(Arg *arg);
+extern void *emallocz(unsigned int size);	/* allocates zero-initialized memory, exits on error */
+extern void eprint(const char *errstr, ...);	/* prints error string and exits with return code 1 */
+extern void *erealloc(void *ptr, unsigned int size);	/* reallocates memory, exits on error */
+extern void spawn(Arg *arg)			/* forks a new subprocess accordingly to arg's cmd */
 
 /* view.c */
-extern void detach(Client *c);
-extern void dofloat(Arg *arg);
-extern void dotile(Arg *arg);
-extern void focusnext(Arg *arg);
-extern void focusprev(Arg *arg);
-extern Bool isvisible(Client *c);
-extern void resizecol(Arg *arg);
-extern void restack();
-extern void togglemode(Arg *arg);
-extern void toggleview(Arg *arg);
-extern void view(Arg *arg);
-extern void viewall(Arg *arg);
-extern void zoom(Arg *arg);
+extern void detach(Client *c);			/* detaches c from global client list */
+extern void dofloat(Arg *arg);			/* arranges all windows in a floating way, arg is ignored */
+extern void dotile(Arg *arg);			/* arranges all windows in a tiled way, arg is ignored */
+extern void focusnext(Arg *arg);		/* focuses next visible client, arg is ignored  */
+extern void focusprev(Arg *arg);		/* focuses previous visible client, arg is ignored */
+extern Bool isvisible(Client *c);		/* returns True if client is visible */
+extern void resizecol(Arg *arg);		/* resizes the master width accordingly to arg's index value */
+extern void restack();				/* restores z layers of all clients */
+extern void togglemode(Arg *arg);		/* toggles global arrange mode (between dotile and dofloat) */
+extern void toggleview(Arg *arg);		/* makes the tag accordingly to arg's index (in)visible */
+extern void view(Arg *arg);			/* makes the tag accordingly to arg's index visible */
+extern void viewall(Arg *arg);			/* makes all tags visible, arg is ignored */
+extern void zoom(Arg *arg);			/* zooms the focused client to master column, arg is ignored */