We have `NULL' in order to not need to write `(char *)0' anymore.

diff --git a/configure.ac b/configure.ac
index 2fba8974fae5da536d9948005fb6a949d723f7d8..35d1b2d70c73f741304937db76c86240d8a50415 100644 (file)
--- 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 57653ea29589a5a96a5cd47d88a3a5cd0f796eb8..6ca9a3d677127f2c2164541e1600a72771aa1d87 100644 (file)
--- 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 a4b093431271038fe10aa6fb1b8de4e705cd58e1..467718b0a25310cc681ca277f9f1125cc7466afe 100644 (file)
--- 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 391f5c8166b954ef15472ed92fd9a45dd9fcd308..7a4a982692efddf83c9a9ee9c28b26554420f01a 100644 (file)
--- 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 e9257bd7ad0ef2c4517ad1d4c008650bf96c8222..4950330a115d27309764785c8182ab5e1e3d35a7 100644 (file)
--- 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 034aa12a309c8d540f178d5b175da1c88864f1c1..212d35cfde8f7aa1ebed3ea6b321881bf830244b 100644 (file)
--- 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 fc2f7111773fb3f4519a8b253c1ec439553bf8f6..0e7c53a3fc1da80f54c25ca58193d8a20ccc36a1 100644 (file)
--- 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 1834c9207124383d573b83e1c59503be92451640..f7121521c1923e49a3a1ca41b088c562243025f3 100644 (file)
--- 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 615ac71f3c6fa2134f6da3b4d3190e37467e5b17..d5c16d9eb137c9b8fcc7fa6d523560e9dc95df51 100644 (file)
--- 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 44fd19aaeb3208ab314d044eea26a4fe09f5934a..14963b56187282db48b44344c66209a0d6bd5e8f 100644 (file)
--- 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 99ec48c59950de1d8b02498cedf1a235c5b37917..b9342209d57d2268c7134c190f6afa38b54e6d33 100644 (file)
--- 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 10a4a10378eea37a7264bef80efc74c0e3d0143c..36c1eed24da18fcc4ece9557c28fc8dd7fa694d1 100644 (file)
--- 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 a9ae46d72a719d3e39381a3815af56e52be166fc..051e357cf6284a878d7a2328d3fb78dbdced0e48 100644 (file)
--- 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 8d85559a602299e00b8794bdd72727c614c9908f..1534402413499a2b983b5ea6577ca1f4b46b82a9 100644 (file)
--- 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 0d8e39da14339d8c2a986e7079ca1699a64e27aa..59247c2b360c5f2c62b3398c2f91dc134ff3fc17 100644 (file)
--- 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 3fff44a49023ab9d8246fa22dd81348c4fe54865..007adb36d383ff46531eea6897e3a2b09d77be71 100644 (file)
--- 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 032566e2291f28d857b44db1024355129467e988..aefe67f54b00f7905bb2976c57a6fa9ca82ef1b7 100644 (file)
--- 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