The `pid_file` option will now always attempt to write a pid file.

This happens regardless of whether the `-d` argument is used when
running the broker.

Closes #1845. Thanks to habazut.

ChangeLog.txt

@@ -22,6 +22,8 @@ Breaking changes:
   method, or set `allow_anonymous true`. When the broker is run without a
   configured listener, and so binds to the loopback interface, anonymous
   connections are allowed.
+- The `pid_file` option will now always attempt to write a pid file,
+  regardless of whether the `-d` argument is used when running the broker.
 
 Broker:
 - When running as root, if dropping privileges to the "mosquitto" user fails,

man/mosquitto.conf.5.xml

@@ -860,9 +860,7 @@ log_timestamp_format %Y-%m-%dT%H:%M:%S
 				<listitem>
 					<para>Write a pid file to the file specified. If not given
 						(the default), no pid file will be written. If the pid
-						file cannot be written, mosquitto will exit. This
-						option only has an effect is mosquitto is run in daemon
-						mode.</para>
+						file cannot be written, mosquitto will exit.</para>
 					<para>If mosquitto is being automatically started by an
 						init script it will usually be required to write a pid
 						file. This should then be configured as e.g.

src/mosquitto.c

@@ -395,7 +395,7 @@ int pid__write(struct mosquitto_db *db)
 {
 	FILE *pid;
 
-	if(db->config->daemon && db->config->pid_file){
+	if(db->config->pid_file){
 		pid = mosquitto__fopen(db->config->pid_file, "wt", false);
 		if(pid){
 			fprintf(pid, "%d", getpid());