+#include <stdio.h> /* for FILE typedef */
+#include <stdint.h> /* for uint8_t, uint16_t, uint32_t */
+
+
+
+/* Wrappers to fopen(), fclose(), fgets() and fwrite() from function called "f",
+ * calling exit_err() upon error with appropriate error messages.
+ */
+extern FILE * try_fopen(char * path, char * mode, char * f);
+extern void try_fclose(FILE * file, char * f);
+extern void try_fwrite(void * ptr, size_t size, size_t nmemb, FILE * stream,
+ char * f);
+extern void try_fputc(uint8_t c, FILE * file, char * f);
+
+/* Wrapper to calling fgets() from function called "f". The return code of
+ * fgets() is returned unless it is NULL *and* ferror() indicates that an error
+ * occured; otherwise end of file is assumed and NULL is returned properly.
+ */
+extern char * try_fgets(char * line, int size, FILE * file, char * f);