-uint16_t read_uint16_bigendian(FILE * file);
-void write_uint16_bigendian(uint16_t x, FILE * file);
-uint32_t read_uint32_bigendian(FILE * file);
-void write_uint32_bigendian(uint32_t x, FILE * file);
+/* readwrite.h:
+ *
+ * Routines for reading/writing multibyte data from/to files. They ensure a
+ * defined endianness.
+ */
+#ifndef READWRITE_H
+#define READWRITE_H
+
+#include <stdio.h>
+#include <stdint.h>
+
+extern uint16_t read_uint16_bigendian( FILE * file );
+extern uint32_t read_uint32_bigendian( FILE * file );
+extern void write_uint16_bigendian( uint16_t x, FILE * file );
+extern void write_uint32_bigendian( uint32_t x, FILE * file );
+
+#endif