Handout

compiler/libc.cc

@@ -0,0 +1,45 @@
+#include "libc.h"
+
+/*! \brief Function pointer for initialization/finalization functions for global
+ * objects required since GCC 4.7 and later.
+ *
+ * These symbols appear kind of magically due to the compiler
+ */
+extern void (*__preinit_array_start[])();
+extern void (*__preinit_array_end[])();
+extern void (*__init_array_start[])();
+extern void (*__init_array_end[])();
+extern void (*__fini_array_start[])();
+extern void (*__fini_array_end[])();
+
+namespace CSU {
+
+void initializer() {
+  const unsigned int preinit_size = __preinit_array_end - __preinit_array_start;
+  for (unsigned int i = 0; i != preinit_size; ++i) {
+    (*__preinit_array_start[i])();
+  }
+
+  const size_t size = __init_array_end - __init_array_start;
+  for (size_t i = 0; i < size; i++) {
+    (*__init_array_start[i])();
+  }
+}
+
+void finalizer() {
+  const unsigned int fini_size = __fini_array_end - __fini_array_start;
+  for (unsigned int i = 0; i != fini_size; ++i) {
+    (*__fini_array_start[i])();
+  }
+}
+
+}  // namespace CSU
+
+extern "C" int atexit(void (*func)(void)) {
+  // Registers a function that will be executed on exit.
+  // We simply ignore those functions, as we don't need them for our operating
+  // systems.
+  (void)func;
+
+  return 0;
+}