diff --git a/src/output.c b/src/output.c
index 5a8df36..e5c2fcd 100644
--- a/src/output.c
+++ b/src/output.c
@@ -37,7 +37,7 @@ static size_t _rjp__write_value(char* dest, RJP_value* val){
 		size_t ret;
 		switch(val->type){
 		case json_integer:
-			ret = sprintf(dest, "%li", val->integer);
+			ret = sprintf(dest, "%lli", val->integer);
 			break;
 		case json_dfloat:
 			ret = sprintf(dest, "%lf", val->dfloat);
diff --git a/src/rjp.c b/src/rjp.c
index 2962789..50275dc 100644
--- a/src/rjp.c
+++ b/src/rjp.c
@@ -85,7 +85,7 @@ void rjp_set_value(RJP_value* dest, RJP_value value){
 	*dest = value;
 	dest->parent = p;
 }
-RJP_value rjp_integer(long i){
+RJP_value rjp_integer(RJP_int i){
 	return (RJP_value){.integer = i, .type = json_integer};
 }
 RJP_value rjp_boolean(char b){
diff --git a/src/strings.c b/src/strings.c
index 218b543..46f7186 100644
--- a/src/strings.c
+++ b/src/strings.c
@@ -301,7 +301,7 @@ size_t _rjp__array_strlen(RJP_value* arr){
 	for(;element_list;element_list = element_list->next){
 		switch(element_list->value.type){
 		case json_integer:
-			count += snprintf(NULL, 0, "%li", element_list->value.integer);
+			count += snprintf(NULL, 0, "%lli", element_list->value.integer);
 			break;
 		case json_dfloat:
 			count += snprintf(NULL, 0, "%lf", element_list->value.dfloat);
@@ -350,7 +350,7 @@ size_t _rjp__object_strlen(RJP_value* root){
 size_t _rjp__value_strlen(RJP_value* root){
 	switch(root->type){
 	case json_integer:
-		return snprintf(NULL, 0, "%li", root->integer);
+		return snprintf(NULL, 0, "%lli", root->integer);
 	case json_dfloat:
 		return snprintf(NULL, 0, "%lf", root->dfloat);
 	case json_boolean: