From 7e3bc577e84e13a47005a706718bd6ec0e6a0e0a Mon Sep 17 00:00:00 2001
From: markus schnalke <meillo@marmaro.de>
Date: Fri, 9 Dec 2011 18:44:19 +0100
Subject: [PATCH] We have `NULL' in order to not need to write `(char *)0'
 anymore.

---
 configure.ac         |    2 +-
 sbr/context_read.c   |   14 +++++++-------
 sbr/ext_hook.c       |    6 +++---
 sbr/folder_addmsg.c  |    4 ++--
 sbr/folder_delmsgs.c |    2 +-
 uip/annosbr.c        |    6 +++---
 uip/burst.c          |    4 ++--
 uip/inc.c            |    6 +++---
 uip/install-mh.c     |    2 +-
 uip/mhstoresbr.c     |    2 +-
 uip/rcvstore.c       |    4 ++--
 uip/rmf.c            |    2 +-
 uip/send.c           |    2 +-
 uip/sendsbr.c        |   30 +++++++++++++++---------------
 uip/sortm.c          |    4 ++--
 uip/viamail.c        |    2 +-
 uip/whatnowsbr.c     |   48 ++++++++++++++++++++++++------------------------
 17 files changed, 70 insertions(+), 70 deletions(-)

diff --git a/configure.ac b/configure.ac
index 2fba897..35d1b2d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -602,7 +602,7 @@ main()
 {
 	char buf[4096];
 	int r1 = tgetent(buf, "vt100");
-	int r2 = tgetent((char*)0,"vt100");
+	int r2 = tgetent(NULL,"vt100");
 	if (r1 >= 0 && r1 == r2) {
 		char tbuf[1024], *u;
 		u = tbuf;
diff --git a/sbr/context_read.c b/sbr/context_read.c
index 57653ea..6ca9a3d 100644
--- a/sbr/context_read.c
+++ b/sbr/context_read.c
@@ -47,7 +47,7 @@ context_read(void)
 	** Find user's home directory. Try the HOME environment variable first,
 	** the home directory field in the password file if that's not found.
 	*/
-	if ((mypath = getenv("HOME")) == (char *)0) {
+	if ((mypath = getenv("HOME")) == NULL) {
 		if ((pw = getpwuid(getuid())) == (struct passwd *)0 ||
 					*pw->pw_dir == '\0')
 			adios(NULL, "cannot determine your home directory");
@@ -67,15 +67,15 @@ context_read(void)
 		defpath = getcpy(expanddir(cp));
 
 		if (stat(defpath, &st) != -1 && (st.st_mode & S_IFREG) == 0)
-			adios((char *)0, "`%s' specified by your MH environment variable is not a normal file", cp);
+			adios(NULL, "`%s' specified by your MH environment variable is not a normal file", cp);
 
 		if ((ib = fopen(defpath, "r")) == (FILE *)0)
-			adios((char *)0, "unable to read the `%s' profile specified by your MH environment variable", defpath);
+			adios(NULL, "unable to read the `%s' profile specified by your MH environment variable", defpath);
 	} else {
 		defpath = concat(mypath, "/", mh_profile, NULL);
 
 		if ((ib = fopen(defpath, "r")) == (FILE *)0)
-			adios((char *)0, "Doesn't look like nmh is installed.  Run install-mh to do so.");
+			adios(NULL, "Doesn't look like nmh is installed.  Run install-mh to do so.");
 
 		cp = mh_profile;
 	}
@@ -89,7 +89,7 @@ context_read(void)
 	** one rooted in the home directory.
 	*/
 
-	if ((cp = context_find("path")) == (char *)0)
+	if ((cp = context_find("path")) == NULL)
 		adios(NULL, "Your %s file does not contain a path entry.",
 				defpath);
 
@@ -112,7 +112,7 @@ context_read(void)
 		if (!makedir(nd))
 			adios(NULL, "unable to create %s", nd);
 	} else if ((st.st_mode & S_IFDIR) == 0)
-		adios((char *)0, "`%s' is not a directory", nd);
+		adios(NULL, "`%s' is not a directory", nd);
 
 	/*
 	** Open and read user's context file.  The name of the context
@@ -120,7 +120,7 @@ context_read(void)
 	** environment variable.
 	*/
 
-	if ((cp = getenv("MHCONTEXT")) == (char *)0 || *cp == '\0')
+	if ((cp = getenv("MHCONTEXT")) == NULL || *cp == '\0')
 		cp = context;
 
 	/*
diff --git a/sbr/ext_hook.c b/sbr/ext_hook.c
index a4b0934..467718b 100644
--- a/sbr/ext_hook.c
+++ b/sbr/ext_hook.c
@@ -19,7 +19,7 @@ ext_hook(char *hook_name, char *message_file_name_1, char *message_file_name_2)
 
 	static int did_message = 0; /* set if we've already output a message */
 
-	if ((hook = context_find(hook_name)) == (char *)0)
+	if ((hook = context_find(hook_name)) == NULL)
 		return (OK);
 
 	switch (pid = vfork()) {
@@ -32,7 +32,7 @@ ext_hook(char *hook_name, char *message_file_name_1, char *message_file_name_2)
 		vec[0] = mhbasename(hook);
 		vec[1] = message_file_name_1;
 		vec[2] = message_file_name_2;
-		vec[3] = (char *)0;
+		vec[3] = NULL;
 		execvp(hook, vec);
 		_exit(-1);
 		/* NOTREACHED */
@@ -44,7 +44,7 @@ ext_hook(char *hook_name, char *message_file_name_1, char *message_file_name_2)
 
 	if (status != OK) {
 		if (did_message == 0) {
-			if ((hook = context_find("msg-hook")) != (char *)0)
+			if ((hook = context_find("msg-hook")) != NULL)
 				advise(NULL, hook);
 			else
 				advise(NULL, "external hook (%s) did not work properly.", hook);
diff --git a/sbr/folder_addmsg.c b/sbr/folder_addmsg.c
index 391f5c8..7a4a982 100644
--- a/sbr/folder_addmsg.c
+++ b/sbr/folder_addmsg.c
@@ -136,7 +136,7 @@ folder_addmsg(struct msgs **mpp, char *msgfile, int selected,
 						from_dir, msgfile);
 				ext_hook("ref-hook", oldmsg, newmsg);
 			} else
-				ext_hook("add-hook", newmsg, (char *)0);
+				ext_hook("add-hook", newmsg, NULL);
 
 			return msgnum;
 		} else {
@@ -195,7 +195,7 @@ folder_addmsg(struct msgs **mpp, char *msgfile, int selected,
 								msgfile);
 						ext_hook("ref-hook", oldmsg, newmsg);
 					} else
-						ext_hook("add-hook", newmsg, (char *)0);
+						ext_hook("add-hook", newmsg, NULL);
 
 					return msgnum;
 				}
diff --git a/sbr/folder_delmsgs.c b/sbr/folder_delmsgs.c
index e9257bd..4950330 100644
--- a/sbr/folder_delmsgs.c
+++ b/sbr/folder_delmsgs.c
@@ -94,7 +94,7 @@ folder_delmsgs(struct msgs *mp, int unlink_msgs, int nohook)
 			if (!nohook) {
 				snprintf(msgpath, sizeof (msgpath), "%s/%d",
 						mp->foldpath, msgnum);
-				ext_hook("del-hook", msgpath, (char *)0);
+				ext_hook("del-hook", msgpath, NULL);
 			}
 
 			dp = m_name(msgnum);
diff --git a/uip/annosbr.c b/uip/annosbr.c
index 034aa12..212d35c 100644
--- a/uip/annosbr.c
+++ b/uip/annosbr.c
@@ -135,7 +135,7 @@ annolist(char *file, char *comp, char *text, int number)
 			if (number)
 				printf("%d\t", ++count);
 
-			if (text == (char *)0 && (sp = strrchr(cp, '/')) != (char *)0)
+			if (text == NULL && (sp = strrchr(cp, '/')) != NULL)
 				cp = sp + 1;
 
 			printf("%s\n", cp);
@@ -297,7 +297,7 @@ annosbr(int fd, char *file, char *comp, char *text, int inplace,
 
 			if (strncasecmp(field, comp, length) == 0 && field[length] == ':') {
 				if (delete == 0) {
-					if (text == (char *)0)
+					if (text == NULL)
 						break;
 
 					for (cp = field + length + 1; *cp == ' ' || *cp == '\t'; cp++)
@@ -308,7 +308,7 @@ annosbr(int fd, char *file, char *comp, char *text, int inplace,
 								break;
 					}
 					else {
-						if ((sp = strrchr(cp, '/')) != (char *)0)
+						if ((sp = strrchr(cp, '/')) != NULL)
 							cp = sp + 1;
 
 						if (strcmp(cp, text) == 0)
diff --git a/uip/burst.c b/uip/burst.c
index fc2f711..0e7c53a 100644
--- a/uip/burst.c
+++ b/uip/burst.c
@@ -364,13 +364,13 @@ burst(struct msgs **mpp, int msgnum, struct smsg *smsgs, int numburst,
 				admonish(f3, "unable to rename %s to", f1);
 
 			snprintf(f3, sizeof (f3), "%s/%d", maildir, i);
-			ext_hook("del-hook", f3, (char *)0);
+			ext_hook("del-hook", f3, NULL);
 		}
 		if (rename(f2, f1) == NOTOK)
 			admonish(f1, "unable to rename %s to", f2);
 
 		snprintf(f3, sizeof (f3), "%s/%d", maildir, i);
-		ext_hook("add-hook", f3, (char *)0);
+		ext_hook("add-hook", f3, NULL);
 
 		copy_msg_flags(mp, i, msgnum);
 		mp->msgflags |= SEQMOD;
diff --git a/uip/inc.c b/uip/inc.c
index 1834c92..f712152 100644
--- a/uip/inc.c
+++ b/uip/inc.c
@@ -295,7 +295,7 @@ main(int argc, char **argv)
 	if (stat(newmail, &s1) == NOTOK || s1.st_size == 0)
 		adios(NULL, "no mail to incorporate");
 
-	if ((cp = strdup(newmail)) == (char *)0)
+	if ((cp = strdup(newmail)) == NULL)
 		adios(NULL, "error allocating memory to copy newmail");
 
 	newmail = cp;
@@ -304,7 +304,7 @@ main(int argc, char **argv)
 		folder = getdeffol();
 	maildir = toabsdir(folder);
 
-	if ((maildir_copy = strdup(maildir)) == (char *)0)
+	if ((maildir_copy = strdup(maildir)) == NULL)
 		adios(maildir, "error allocating memory to copy maildir");
 
 	if (!folder_exists(maildir)) {
@@ -432,7 +432,7 @@ main(int argc, char **argv)
 
 			snprintf(b, sizeof (b), "%s/%d", maildir_copy,
 					msgnum + 1);
-			ext_hook("add-hook", b, (char *)0);
+			ext_hook("add-hook", b, NULL);
 
 			if (aud)
 				fputs(scanl, aud);
diff --git a/uip/install-mh.c b/uip/install-mh.c
index 615ac71..d5c16d9 100644
--- a/uip/install-mh.c
+++ b/uip/install-mh.c
@@ -85,7 +85,7 @@ main(int argc, char **argv)
 	** if that's not found.
 	*/
 
-	if ((mypath = getenv("HOME")) == (char *)0) {
+	if ((mypath = getenv("HOME")) == NULL) {
 		if ((pw = getpwuid(getuid())) == (struct passwd *)0 ||
 				*pw->pw_dir == '\0')
 			adios(NULL, "cannot determine your home directory");
diff --git a/uip/mhstoresbr.c b/uip/mhstoresbr.c
index 44fd19a..14963b5 100644
--- a/uip/mhstoresbr.c
+++ b/uip/mhstoresbr.c
@@ -867,7 +867,7 @@ output_content_folder(char *folder, char *filename)
 	/* Read the folder. */
 	if ((mp = folder_read(folder))) {
 		/* Link file into folder */
-		msgnum = folder_addmsg(&mp, filename, 0, 0, 0, 0, (char *)0);
+		msgnum = folder_addmsg(&mp, filename, 0, 0, 0, 0, NULL);
 	} else {
 		advise(NULL, "unable to read folder %s", folder);
 		return NOTOK;
diff --git a/uip/rcvstore.c b/uip/rcvstore.c
index 99ec48c..b934220 100644
--- a/uip/rcvstore.c
+++ b/uip/rcvstore.c
@@ -202,8 +202,8 @@ main(int argc, char **argv)
 	** Link message into folder, and possibly add
 	** to the Unseen-Sequence's.
 	*/
-	if ((msgnum = folder_addmsg(&mp, tmpfilenam, 0, unseensw, 0, 0,
-			(char *)0)) == -1)
+	if ((msgnum = folder_addmsg(&mp, tmpfilenam, 0, unseensw, 0, 0, NULL))
+			== -1)
 		done(1);
 
 	/*
diff --git a/uip/rmf.c b/uip/rmf.c
index 10a4a10..36c1eed 100644
--- a/uip/rmf.c
+++ b/uip/rmf.c
@@ -158,7 +158,7 @@ rmf(char *folder)
 	** Run the external delete hook program.
 	*/
 
-	ext_hook("del-hook", maildir, (char *)0);
+	ext_hook("del-hook", maildir, NULL);
 
 	j = strlen(backup_prefix);
 	while ((dp = readdir(dd))) {
diff --git a/uip/send.c b/uip/send.c
index a9ae46d..051e357 100644
--- a/uip/send.c
+++ b/uip/send.c
@@ -109,7 +109,7 @@ main(int argc, char **argv)
 	char *msgs[MAXARGS], *vec[MAXARGS];
 	struct msgs *mp;
 	struct stat st;
-	char *attach = (char *)0;  /* header field name for attachments */
+	char *attach = NULL;  /* header field name for attachments */
 	int attachformat = 0; /* mhbuild format specifier for attachments */
 #ifdef UCI
 	FILE *fp;
diff --git a/uip/sendsbr.c b/uip/sendsbr.c
index 8d85559..1534402 100644
--- a/uip/sendsbr.c
+++ b/uip/sendsbr.c
@@ -103,7 +103,7 @@ sendsbr(char **vec, int vecp, char *drft, struct stat *st,
 	** and modified if desired.
 	*/
 
-	if (attachment_header_field_name != (char *)0) {
+	if (attachment_header_field_name != NULL) {
 		switch (attach(attachment_header_field_name, drft,
 				attachformat)) {
 		case OK:
@@ -167,7 +167,7 @@ sendsbr(char **vec, int vecp, char *drft, struct stat *st,
 
 		if (strlen(composition_file_name) >=
 				sizeof (composition_file_name) - 6)
-			advise((char *)0, "unable to remove original composition file.");
+			advise(NULL, "unable to remove original composition file.");
 
 		else {
 			if ((p = strrchr(composition_file_name, '/')) == NULL)
@@ -203,7 +203,7 @@ attach(char *attachment_header_field_name, char *draft_file_name,
 	*/
 
 	if ((draft_file = fopen(draft_file_name, "r")) == (FILE *)0)
-		adios((char *)0, "can't open draft file `%s'.",
+		adios(NULL, "can't open draft file `%s'.",
 				draft_file_name);
 
 	/*
@@ -272,7 +272,7 @@ attach(char *attachment_header_field_name, char *draft_file_name,
 	if ((has_body && body_file == (FILE *)0) ||
 			composition_file == (FILE *)0) {
 		clean_up_temporary_files();
-		adios((char *)0, "unable to open all of the temporary files.");
+		adios(NULL, "unable to open all of the temporary files.");
 	}
 
 	/*
@@ -400,7 +400,7 @@ make_mime_composition_file_entry(char *file_name, int attachformat)
 	char *p;  /* miscellaneous string pointer */
 	struct stat st;  /* file status buffer */
 
-	content_type = (char *)0;
+	content_type = NULL;
 
 	/*
 	** Check the file name for a suffix.  Scan the context for that
@@ -411,7 +411,7 @@ make_mime_composition_file_entry(char *file_name, int attachformat)
 	** the field, including the dot.
 	*/
 
-	if ((p = strrchr(file_name, '.')) != (char *)0) {
+	if ((p = strrchr(file_name, '.')) != NULL) {
 		for (np = m_defs; np; np = np->n_next) {
 			if (strncasecmp(np->n_name, "mhshow-suffix-", 14) == 0
 					&& mh_strcasecmp(p, np->n_field) == 0)
@@ -429,10 +429,10 @@ make_mime_composition_file_entry(char *file_name, int attachformat)
 	** content type based on this check.
 	*/
 
-	if (content_type == (char *)0) {
+	if (content_type == NULL) {
 		if ((fp = fopen(file_name, "r")) == (FILE *)0) {
 			clean_up_temporary_files();
-			adios((char *)0, "unable to access file \"%s\"",
+			adios(NULL, "unable to access file \"%s\"",
 					file_name);
 		}
 
@@ -461,7 +461,7 @@ make_mime_composition_file_entry(char *file_name, int attachformat)
 
 	if (stat(file_name, &st) == -1 || access(file_name, R_OK) != 0) {
 		clean_up_temporary_files();
-		adios((char *)0, "unable to access file \"%s\"", file_name);
+		adios(NULL, "unable to access file \"%s\"", file_name);
 	}
 
 	switch (attachformat) {
@@ -470,19 +470,19 @@ make_mime_composition_file_entry(char *file_name, int attachformat)
 		fprintf(composition_file,
 				"#%s; name=\"%s\"; x-unix-mode=0%.3ho",
 				content_type, ((p = strrchr(file_name, '/'))
-				== (char *)0) ? file_name : p + 1,
+				== NULL) ? file_name : p + 1,
 				(unsigned short)(st.st_mode & 0777));
 
 		if (strlen(file_name) > MAXPATHLEN) {
 			clean_up_temporary_files();
-			adios((char *)0, "attachment file name `%s' too long.",
+			adios(NULL, "attachment file name `%s' too long.",
 					file_name);
 		}
 
 		sprintf(cmd, "file '%s'", file_name);
 
 		if ((fp = popen(cmd, "r")) != (FILE *)0 &&
-				fgets(cmd, sizeof (cmd), fp) != (char *)0) {
+				fgets(cmd, sizeof (cmd), fp) != NULL) {
 			*strchr(cmd, '\n') = '\0';
 
 			/*
@@ -528,7 +528,7 @@ make_mime_composition_file_entry(char *file_name, int attachformat)
 			fprintf(composition_file,
 				"#%s; name=\"%s\" <>{attachment}",
 				content_type,
-				((p = strrchr(file_name, '/')) == (char *)0) ?
+				((p = strrchr(file_name, '/')) == NULL) ?
 				file_name : p + 1);
 		}
 
@@ -550,13 +550,13 @@ make_mime_composition_file_entry(char *file_name, int attachformat)
 			fprintf(composition_file,
 				"#%s; name=\"%s\" <>{attachment; modification-date=\"%s\"}",
 				content_type,
-				((p = strrchr(file_name, '/')) == (char *)0) ?
+				((p = strrchr(file_name, '/')) == NULL) ?
 				file_name : p + 1, dtime(&st.st_mtime, 0));
 		}
 
 		break;
 	default:
-		adios((char *)0, "unsupported attachformat %d", attachformat);
+		adios(NULL, "unsupported attachformat %d", attachformat);
 	}
 
 	/*
diff --git a/uip/sortm.c b/uip/sortm.c
index 0d8e39d..59247c2 100644
--- a/uip/sortm.c
+++ b/uip/sortm.c
@@ -43,7 +43,7 @@ struct smsg {
 static struct smsg *smsgs;
 int nmsgs;
 
-char *subjsort = (char *) 0;  /* sort on subject if != 0 */
+char *subjsort = NULL;  /* sort on subject if != 0 */
 unsigned long datelimit = 0;
 int submajor = 0;  /* if true, sort on subject-major */
 int verbose;
@@ -126,7 +126,7 @@ main(int argc, char **argv)
 				subjsort = "subject";
 				continue;
 			case NSUBJSW:
-				subjsort = (char *)0;
+				subjsort = NULL;
 				continue;
 
 			case LIMSW:
diff --git a/uip/viamail.c b/uip/viamail.c
index 3fff44a..007adb3 100644
--- a/uip/viamail.c
+++ b/uip/viamail.c
@@ -222,7 +222,7 @@ via_mail(char *mailsw, char *subjsw, char *parmsw, char *descsw,
 	if (verbsw)
 		vec[vecp++] = "-verbose";
 
-	switch (sendsbr(vec, vecp, tmpfil, &st, 0, (char *)0, 0)) {
+	switch (sendsbr(vec, vecp, tmpfil, &st, 0, NULL, 0)) {
 		case DONE:
 		case NOTOK:
 			status++;
diff --git a/uip/whatnowsbr.c b/uip/whatnowsbr.c
index 032566e..aefe67f 100644
--- a/uip/whatnowsbr.c
+++ b/uip/whatnowsbr.c
@@ -128,7 +128,7 @@ WhatNow(int argc, char **argv)
 	char buf[BUFSIZ], prompt[BUFSIZ];
 	char **argp, **arguments;
 	struct stat st;
-	char *attach = (char *)0;  /* attachment header field name */
+	char *attach = NULL;  /* attachment header field name */
 	char cwd[MAXPATHLEN + 1];  /* current working directory */
 	char file[MAXPATHLEN + 1];  /* file name buffer */
 	char shell[MAXPATHLEN + 1];  /* shell response buffer */
@@ -148,7 +148,7 @@ WhatNow(int argc, char **argv)
 	** Get the initial current working directory.
 	*/
 
-	if (getcwd(cwd, sizeof (cwd)) == (char *)0) {
+	if (getcwd(cwd, sizeof (cwd)) == NULL) {
 		adios("getcwd", "could not get working directory");
 	}
 
@@ -188,7 +188,7 @@ WhatNow(int argc, char **argv)
 				continue;
 
 			case ATTACHSW:
-				if (attach != (char *)0)
+				if (attach != NULL)
 					adios(NULL, "only one attachment header field name at a time!");
 				if (!(attach = *argp++) || *attach == '-')
 					adios(NULL, "missing argument to %s",
@@ -300,7 +300,7 @@ WhatNow(int argc, char **argv)
 			** the absolute path.
 			*/
 
-			if (*(argp+1) == (char *)0) {
+			if (*(argp+1) == NULL) {
 				sprintf(buf, "$SHELL -c \"cd;pwd\"");
 			} else {
 				writesomecmd(buf, BUFSIZ, "cd", "pwd", argp);
@@ -308,7 +308,7 @@ WhatNow(int argc, char **argv)
 			if ((f = popen_in_dir(cwd, buf, "r")) != (FILE *)0) {
 				fgets(cwd, sizeof (cwd), f);
 
-				if (strchr(cwd, '\n') != (char *)0)
+				if (strchr(cwd, '\n') != NULL)
 						*strchr(cwd, '\n') = '\0';
 
 				pclose(f);
@@ -344,15 +344,15 @@ WhatNow(int argc, char **argv)
 			** -n    numbers listing
 			*/
 
-			if (attach == (char *)0) {
-				advise((char *)0, "can't list because no header field name was given.");
+			if (attach == NULL) {
+				advise(NULL, "can't list because no header field name was given.");
 				break;
 			}
 
-			l = (char *)0;
+			l = NULL;
 			n = 0;
 
-			while (*++argp != (char *)0) {
+			while (*++argp != NULL) {
 				if (strcmp(*argp, "-l") == 0)
 					l = "/";
 
@@ -370,7 +370,7 @@ WhatNow(int argc, char **argv)
 			}
 
 			if (n == -1)
-				advise((char *)0, "usage is alist [-ln].");
+				advise(NULL, "usage is alist [-ln].");
 
 			else
 				annolist(drft, attach, l, n);
@@ -382,13 +382,13 @@ WhatNow(int argc, char **argv)
 			** Attach files to current draft.
 			*/
 
-			if (attach == (char *)0) {
-				advise((char *)0, "can't attach because no header field name was given.");
+			if (attach == NULL) {
+				advise(NULL, "can't attach because no header field name was given.");
 				break;
 			}
 
-			if (*(argp+1) == (char *)0) {
-				advise((char *)0, "attach command requires file argument(s).");
+			if (*(argp+1) == NULL) {
+				advise(NULL, "attach command requires file argument(s).");
 				break;
 			}
 
@@ -412,7 +412,7 @@ WhatNow(int argc, char **argv)
 
 			if ((f = popen_in_dir(cwd, buf, "r")) != (FILE *)0) {
 				while (fgets(shell, sizeof (shell), f)
-						!= (char *)0) {
+						!= NULL) {
 					*(strchr(shell, '\n')) = '\0';
 
 					if (*shell == '/')
@@ -438,8 +438,8 @@ WhatNow(int argc, char **argv)
 			** Detach files from current draft.
 			*/
 
-			if (attach == (char *)0) {
-				advise((char *)0, "can't detach because no header field name was given.");
+			if (attach == NULL) {
+				advise(NULL, "can't detach because no header field name was given.");
 				break;
 			}
 
@@ -450,7 +450,7 @@ WhatNow(int argc, char **argv)
 			*/
 
 			for (n = 0, arguments = argp + 1;
-					*arguments != (char *)0;
+					*arguments != NULL;
 					arguments++) {
 				if (strcmp(*arguments, "-n") == 0) {
 						n = 1;
@@ -468,7 +468,7 @@ WhatNow(int argc, char **argv)
 
 			if (n == 1) {
 				for (arguments = argp + 1;
-						*arguments != (char *)0;
+						*arguments != NULL;
 						arguments++) {
 					if (strcmp(*arguments, "-n") == 0)
 						continue;
@@ -478,7 +478,7 @@ WhatNow(int argc, char **argv)
 						annotate(drft, attach, NULL,
 								1, 0, n, 1);
 
-						for (argp = arguments + 1; *argp != (char *)0; argp++) {
+						for (argp = arguments + 1; *argp != NULL; argp++) {
 							if (atoi(*argp) > n) {
 								if (atoi(*argp) == 1)
 									*argp = "";
@@ -555,15 +555,15 @@ writesomecmd(char *buf, int bufsz, char *cmd, char *trailcmd, char **argp)
 	*/
 	int trailln = strlen(trailcmd) + 3;
 	if (ln < 0 || ln + trailln > bufsz)
-		adios((char *)0, "arguments too long");
+		adios(NULL, "arguments too long");
 
 	cp = buf + ln;
 
-	while (*++argp != (char *)0) {
+	while (*++argp != NULL) {
 		ln = strlen(*argp);
 		/* +1 for leading space */
 		if (ln + trailln + 1 > bufsz - (cp-buf))
-			adios((char *)0, "arguments too long");
+			adios(NULL, "arguments too long");
 		*cp++ = ' ';
 		memcpy(cp, *argp, ln+1);
 		cp += ln;
@@ -1072,7 +1072,7 @@ sendit(char *sp, char **arg, char *file, int pushed)
 	char *cp, buf[BUFSIZ], **argp;
 	char **arguments, *vec[MAXARGS];
 	struct stat st;
-	char *attach = (char *)0;  /* attachment header field name */
+	char *attach = NULL;  /* attachment header field name */
 	int attachformat = 0;  /* mhbuild format specifier for attachments */
 
 #ifndef lint
-- 
1.7.10.4