diff --git a/qse/include/qse/si/AppRoot.hpp b/qse/include/qse/si/AppRoot.hpp
index 4551f095..368c7d6f 100644
--- a/qse/include/qse/si/AppRoot.hpp
+++ b/qse/include/qse/si/AppRoot.hpp
@@ -42,6 +42,9 @@ public:
 
 	int daemonize (bool chdir_to_root = true, int fork_count = 1) QSE_CPP_NOEXCEPT;
 
+	int chroot (const qse_wchar_t* wpath) QSE_CPP_NOEXCEPT;
+	int chroot (const qse_mchar_t* mpath) QSE_CPP_NOEXCEPT;
+
 protected:
 	bool _root_only;
 
diff --git a/qse/lib/si/AppRoot.cpp b/qse/lib/si/AppRoot.cpp
index 1daa1896..9ece85c7 100644
--- a/qse/lib/si/AppRoot.cpp
+++ b/qse/lib/si/AppRoot.cpp
@@ -49,14 +49,7 @@ int AppRoot::daemonize (bool chdir_to_root, int fork_count) QSE_CPP_NOEXCEPT
 		}
 
 		int n = QSE_FORK();
-		if (n == -1)
-		{
-			//throw DaemonError ("can't xp_fork");
-			//if (err_code) *err_code = ERR_FORK;
-			return -1;
-		}
-
-		// the parent exits
+		if (n == -1) return -1;
 		if (n != 0) QSE_EXIT(0); // TODO: should i call exit() in stdlib.h? 
 	}
 
@@ -128,6 +121,16 @@ int AppRoot::switchUser () QSE_CPP_NOEXCEPT
 }
 #endif
 
+
+int AppRoot::chroot (const qse_mchar_t* mpath) QSE_CPP_NOEXCEPT
+{
+	QSE_CHROOT (mpath);
+}
+
+int AppRoot::chroot (const qse_wchar_t* mpath) QSE_CPP_NOEXCEPT
+{
+}
+
 void AppRoot::on_signal () QSE_CPP_NOEXCEPT
 {
 }
diff --git a/qse/lib/si/log.c b/qse/lib/si/log.c
index d9472baf..90dadb89 100644
--- a/qse/lib/si/log.c
+++ b/qse/lib/si/log.c
@@ -229,7 +229,7 @@ int qse_log_init (qse_log_t* log, qse_mmgr_t* mmgr, const qse_char_t* ident, int
 	log->t.syslog_remote.sock = -1; 
 
 	if (potflags & QSE_LOG_FILE) log->flags |= QSE_LOG_FILE;
-	if (target->file)
+	if (target && target->file)
 	{
 		if (qse_strlen(target->file) >= QSE_COUNTOF(log->t.file.pathbuf))
 		{
@@ -247,7 +247,7 @@ int qse_log_init (qse_log_t* log, qse_mmgr_t* mmgr, const qse_char_t* ident, int
 	if (potflags & QSE_LOG_SYSLOG) log->flags |= QSE_LOG_SYSLOG;
 
 	if (potflags & QSE_LOG_SYSLOG_REMOTE) log->flags |= QSE_LOG_SYSLOG_REMOTE;
-	if (qse_skadfamily(&target->syslog_remote) >= 0) log->t.syslog_remote.addr = target->syslog_remote;
+	if (target && qse_skadfamily(&target->syslog_remote) >= 0) log->t.syslog_remote.addr = target->syslog_remote;
 
 	if (ident) qse_strxcpy (log->ident, QSE_COUNTOF(log->ident), ident);
 	if (qse_mtx_init(&log->mtx, mmgr) <= -1) 
@@ -381,7 +381,7 @@ int qse_log_settarget (qse_log_t* log, int flags, const qse_log_target_t* target
 	/* If you just want to set the target file path without enable QSE_LOG_FILE,
 	 * just set target->file without QSE_LOG_FILE in the flags.
 	 * later, you can call this function with QSE_LOG_FILE set but with target->file or QSE_NULL */
-	if (target->file) 
+	if (target && target->file) 
 	{
 		if (log->t.file.path && log->t.file.path != log->t.file.pathbuf) QSE_MMGR_FREE (log->mmgr, log->t.file.path);
 
@@ -400,7 +400,7 @@ int qse_log_settarget (qse_log_t* log, int flags, const qse_log_target_t* target
 	if (flags & QSE_LOG_SYSLOG) log->flags |= QSE_LOG_SYSLOG;
 
 	if (flags & QSE_LOG_SYSLOG_REMOTE) log->flags |= QSE_LOG_SYSLOG_REMOTE;
-	if (qse_skadfamily(&target->syslog_remote) >= 0) log->t.syslog_remote.addr = target->syslog_remote;
+	if (target && qse_skadfamily(&target->syslog_remote) >= 0) log->t.syslog_remote.addr = target->syslog_remote;
 
 	return 0;
 }