-void irix_locking_callback(int mode, int type, char *file, int line);
-void solaris_locking_callback(int mode, int type, char *file, int line);
-void win32_locking_callback(int mode, int type, char *file, int line);
-void pthreads_locking_callback(int mode, int type, char *file, int line);
-void netware_locking_callback(int mode, int type, char *file, int line);
+void irix_locking_callback(int mode, int type, const char *file, int line);
+void solaris_locking_callback(int mode, int type, const char *file, int line);
+void win32_locking_callback(int mode, int type, const char *file, int line);
+void pthreads_locking_callback(int mode, int type, const char *file, int line);
+void netware_locking_callback(int mode, int type, const char *file, int line);