diff --git a/rrd.c b/rrd.c
index f73aabd..5981e12 100644
--- a/rrd.c
+++ b/rrd.c
@@ -60,7 +60,7 @@ PHP_FUNCTION(rrd_fetch)
 	char **ds_namv; /* list of data source names */
 	rrd_value_t *ds_data; /* all data from all sources */
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "sa", &filename,
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "pa", &filename,
 		&filename_length, &zv_arr_options) == FAILURE) {
 		return;
 	}
@@ -155,7 +155,7 @@ PHP_FUNCTION(rrd_first)
 	/* return value from rrd_first_r call */
 	time_t rrd_first_return_val;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "s|l", &filename,
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "p|l", &filename,
 		&filename_length, &rraindex) == FAILURE) {
 		return;
 	}
@@ -190,7 +190,7 @@ PHP_FUNCTION(rrd_last)
 	/* return value from rrd_first_r call */
 	time_t rrd_last_return_val;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "s", &filename,
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "p", &filename,
 		&filename_length) == FAILURE) {
 		return;
 	}
@@ -226,7 +226,7 @@ PHP_FUNCTION(rrd_lastupdate)
 	char **ds_namv;
 	char **last_ds;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "s", &filename,
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "p", &filename,
 		&filename_length) == FAILURE) {
 		return;
 	}
@@ -309,7 +309,7 @@ PHP_FUNCTION(rrd_restore)
 	zval zv_options;
 	rrd_args *argv;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "ss|a", &xml_filename,
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "pp|a", &xml_filename,
 		&xml_filename_length, &rrd_filename, &rrd_filename_length,
 		&zv_arr_options) == FAILURE) {
 		return;
@@ -356,7 +356,7 @@ PHP_FUNCTION(rrd_tune)
 	zval *zv_arr_options;
 	rrd_args *argv;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "sa", &filename,
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "pa", &filename,
 		&filename_length, &zv_arr_options) == FAILURE) {
 		return;
 	}
diff --git a/rrd_create.c b/rrd_create.c
index 3925a01..97aeedb 100644
--- a/rrd_create.c
+++ b/rrd_create.c
@@ -108,7 +108,7 @@ PHP_METHOD(RRDCreator, __construct)
 	long step = 0;
 	int argc = ZEND_NUM_ARGS();
 
-	if (zend_parse_parameters(argc, "s|sl", &path, &path_length,
+	if (zend_parse_parameters(argc, "p|sl", &path, &path_length,
 		&start_time, &start_time_length, &step) == FAILURE) {
 		return;
 	}
@@ -288,7 +288,7 @@ PHP_FUNCTION(rrd_create)
 	zval *zv_arr_options;
 	rrd_args *argv;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "sa", &filename,
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "pa", &filename,
 		&filename_length, &zv_arr_options) == FAILURE) {
 		return;
 	}
diff --git a/rrd_graph.c b/rrd_graph.c
index aea6511..246597e 100644
--- a/rrd_graph.c
+++ b/rrd_graph.c
@@ -91,7 +91,7 @@ PHP_METHOD(RRDGraph, __construct)
 	char *path;
 	size_t path_length;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "s", &path, &path_length) == FAILURE) {
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "p", &path, &path_length) == FAILURE) {
 		return;
 	}
 
@@ -302,7 +302,7 @@ PHP_FUNCTION(rrd_graph)
 	double ymin,ymax;
 	char **calcpr;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "sa", &filename,
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "pa", &filename,
 		&filename_length, &zv_arr_options) == FAILURE) {
 		return;
 	}
diff --git a/rrd_info.c b/rrd_info.c
index 553f0cd..bbc9b2f 100644
--- a/rrd_info.c
+++ b/rrd_info.c
@@ -33,7 +33,7 @@ PHP_FUNCTION(rrd_info)
 	/* return value from rrd_info_r() */
 	rrd_info_t *rrd_info_data;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "s", &filename,
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "p", &filename,
 		&filename_length) == FAILURE) {
 		return;
 	}
diff --git a/rrd_update.c b/rrd_update.c
index 35b49e0..1acd44a 100644
--- a/rrd_update.c
+++ b/rrd_update.c
@@ -85,7 +85,7 @@ PHP_METHOD(RRDUpdater, __construct)
 	char *path;
 	size_t path_length;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "s", &path, &path_length) == FAILURE) {
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "p", &path, &path_length) == FAILURE) {
 		return;
 	}
 
@@ -219,7 +219,7 @@ PHP_FUNCTION(rrd_update)
 	zval *zv_arr_options;
 	rrd_args *argv;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "sa", &filename,
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "pa", &filename,
 		&filename_length, &zv_arr_options) == FAILURE) {
 		return;
 	}