diff --git a/doc/apiref.rst b/doc/apiref.rst
index dc82527..8623623 100644
--- a/doc/apiref.rst
+++ b/doc/apiref.rst
@@ -392,18 +392,18 @@ can be ORed together to obtain *flags*.
 The following functions perform the actual JSON encoding. The result
 is in UTF-8.
 
-.. cfunction:: char *json_dumps(const json_t *root, uint32_t flags)
+.. cfunction:: char *json_dumps(const json_t *root, unsigned long flags)
 
    Returns the JSON representation of *root* as a string, or *NULL* on
    error. *flags* is described above. The return value must be freed
    by the caller using :cfunc:`free()`.
 
-.. cfunction:: int json_dumpf(const json_t *root, FILE *output, uint32_t flags)
+.. cfunction:: int json_dumpf(const json_t *root, FILE *output, unsigned long flags)
 
    Write the JSON representation of *root* to the stream *output*.
    *flags* is described above. Returns 0 on success and -1 on error.
 
-.. cfunction:: int json_dump_file(const json_t *json, const char *path, uint32_t flags)
+.. cfunction:: int json_dump_file(const json_t *json, const char *path, unsigned long flags)
 
    Write the JSON representation of *root* to the file *path*. If
    *path* already exists, it is overwritten. *flags* is described
diff --git a/src/dump.c b/src/dump.c
index 9505b7f..042b0c7 100644
--- a/src/dump.c
+++ b/src/dump.c
@@ -38,7 +38,7 @@ static int dump_to_file(const char *buffer, int size, void *data)
 /* 256 spaces (the maximum indentation size) */
 static char whitespace[] = "                                                                                                                                                                                                                                                                ";
 
-static int dump_indent(uint32_t flags, int depth, dump_func dump, void *data)
+static int dump_indent(unsigned long flags, int depth, dump_func dump, void *data)
 {
     if(JSON_INDENT(flags) > 0)
     {
@@ -111,7 +111,7 @@ static int dump_string(const char *str, dump_func dump, void *data)
     return dump("\"", 1, data);
 }
 
-static int do_dump(const json_t *json, uint32_t flags, int depth,
+static int do_dump(const json_t *json, unsigned long flags, int depth,
                    dump_func dump, void *data)
 {
     switch(json_typeof(json)) {
@@ -232,7 +232,7 @@ static int do_dump(const json_t *json, uint32_t flags, int depth,
 }
 
 
-char *json_dumps(const json_t *json, uint32_t flags)
+char *json_dumps(const json_t *json, unsigned long flags)
 {
     strbuffer_t strbuff;
     char *result;
@@ -255,7 +255,7 @@ char *json_dumps(const json_t *json, uint32_t flags)
     return result;
 }
 
-int json_dumpf(const json_t *json, FILE *output, uint32_t flags)
+int json_dumpf(const json_t *json, FILE *output, unsigned long flags)
 {
     if(!json_is_array(json) && !json_is_object(json))
         return -1;
@@ -265,7 +265,7 @@ int json_dumpf(const json_t *json, FILE *output, uint32_t flags)
     return dump_to_file("\n", 1, (void *)output);
 }
 
-int json_dump_file(const json_t *json, const char *path, uint32_t flags)
+int json_dump_file(const json_t *json, const char *path, unsigned long flags)
 {
     int result;
 
diff --git a/src/jansson.h b/src/jansson.h
index 2e8582b..b5cdddb 100644
--- a/src/jansson.h
+++ b/src/jansson.h
@@ -124,8 +124,8 @@ json_t *json_load_file(const char *path, json_error_t *error);
 
 #define JSON_INDENT(n)   (n & 0xFF)
 
-char *json_dumps(const json_t *json, uint32_t flags);
-int json_dumpf(const json_t *json, FILE *output, uint32_t flags);
-int json_dump_file(const json_t *json, const char *path, uint32_t flags);
+char *json_dumps(const json_t *json, unsigned long flags);
+int json_dumpf(const json_t *json, FILE *output, unsigned long flags);
+int json_dump_file(const json_t *json, const char *path, unsigned long flags);
 
 #endif