--- a/src/mail/ngx_mail_core_module.c
+++ b/src/mail/ngx_mail_core_module.c
@@ -304,7 +304,7 @@ ngx_mail_core_merge_srv_conf(ngx_conf_t 
     ngx_mail_core_srv_conf_t *prev = parent;
     ngx_mail_core_srv_conf_t *conf = child;
 
-    u_char      *p, *auth_p, *last_p;
+    u_char      *p, *auth, *last;
     size_t       size, stls_only_size;
     ngx_str_t   *c, *d;
     ngx_uint_t   i, m, smtp_auth_enabled;
@@ -518,7 +518,7 @@ ngx_mail_core_merge_srv_conf(ngx_conf_t 
         p = ngx_cpymem(p, c[i].data, c[i].len);
     }
 
-    auth_p = p;
+    auth = p;
 
     for (m = NGX_MAIL_AUTH_PLAIN_ENABLED, i = 0;
          m <= NGX_MAIL_AUTH_CRAM_MD5_ENABLED;
@@ -550,8 +550,8 @@ ngx_mail_core_merge_srv_conf(ngx_conf_t 
     *p++ = CR; *p = LF;
 
 
-    size = (auth_p - conf->imap_capability.data) + sizeof(CRLF) - 1
-        + sizeof(" STARTTLS LOGINDISABLED") - 1;
+    size = (auth - conf->imap_capability.data) + sizeof(CRLF) - 1
+            + sizeof(" STARTTLS LOGINDISABLED") - 1;
 
     p = ngx_palloc(cf->pool, size);
     if (p == NULL) {
@@ -562,7 +562,7 @@ ngx_mail_core_merge_srv_conf(ngx_conf_t 
     conf->imap_starttls_only_capability.data = p;
 
     p = ngx_cpymem(p, conf->imap_capability.data,
-                   auth_p - conf->imap_capability.data);
+                   auth - conf->imap_capability.data);
     p = ngx_cpymem(p, " STARTTLS LOGINDISABLED",
                    sizeof(" STARTTLS LOGINDISABLED") - 1);
     *p++ = CR; *p = LF;
@@ -632,22 +632,22 @@ ngx_mail_core_merge_srv_conf(ngx_conf_t 
     conf->smtp_capability.len = size;
     conf->smtp_capability.data = p;
 
-    last_p = p;
+    last = p;
     *p++ = '2'; *p++ = '5'; *p++ = '0'; *p++ = '-';
     p = ngx_cpymem(p, conf->server_name.data, conf->server_name.len);
     *p++ = CR; *p++ = LF;
 
     for (i = 0; i < conf->smtp_capabilities.nelts; i++) {
-        last_p = p;
+        last = p;
         *p++ = '2'; *p++ = '5'; *p++ = '0'; *p++ = '-';
         p = ngx_cpymem(p, c[i].data, c[i].len);
         *p++ = CR; *p++ = LF;
     }
 
-    auth_p = p;
+    auth = p;
 
     if (smtp_auth_enabled) {
-        last_p = p;
+        last = p;
 
         *p++ = '2'; *p++ = '5'; *p++ = '0'; *p++ = ' ';
         *p++ = 'A'; *p++ = 'U'; *p++ = 'T'; *p++ = 'H';
@@ -666,7 +666,7 @@ ngx_mail_core_merge_srv_conf(ngx_conf_t 
         *p++ = CR; *p = LF;
 
     } else {
-        last_p[3] = ' ';
+        last[3] = ' ';
     }
 
     size += sizeof("250 STARTTLS" CRLF) - 1;
@@ -686,10 +686,10 @@ ngx_mail_core_merge_srv_conf(ngx_conf_t 
     *p++ = CR; *p = LF;
 
     p = conf->smtp_starttls_capability.data
-        + (last_p - conf->smtp_capability.data) + 3;
+        + (last - conf->smtp_capability.data) + 3;
     *p = '-';
 
-    size = (auth_p - conf->smtp_capability.data)
+    size = (auth - conf->smtp_capability.data)
         + sizeof("250 STARTTLS" CRLF) - 1; 
 
     p = ngx_palloc(cf->pool, size);
@@ -701,13 +701,13 @@ ngx_mail_core_merge_srv_conf(ngx_conf_t 
     conf->smtp_starttls_only_capability.data = p;
 
     p = ngx_cpymem(p, conf->smtp_capability.data,
-                   auth_p - conf->smtp_capability.data);
+                   auth - conf->smtp_capability.data);
 
     p = ngx_cpymem(p, "250 STARTTLS" CRLF, sizeof("250 STARTTLS" CRLF) - 1);
 
-    if (last_p < auth_p) {
+    if (last < auth) {
         p = conf->smtp_starttls_only_capability.data
-            + (last_p - conf->smtp_capability.data) + 3;
+            + (last - conf->smtp_capability.data) + 3;
         *p = '-';
     }