C++ ctor question (linux)

constructor (priority)

constructor (priority)

constructor (priority)

.ctors          :
  {
    /* gcc uses crtbegin.o to find the start of
       the constructors, so we make sure it is
       first.  Because this is a wildcard, it
       doesn't matter if the user does not
       actually link against crtbegin.o; the
       linker won't look for a file to match a
       wildcard.  The wildcard also means that it
       doesn't matter which directory crtbegin.o
       is in.  */
    KEEP (*crtbegin.o(.ctors))
    KEEP (*crtbegin?.o(.ctors))
    /* We don't want to include the .ctor section from
       the crtend.o file until after the sorted ctors.
       The .ctor section from the crtend file contains the
       end of ctors marker and it must be last */
    KEEP (*(EXCLUDE_FILE (*crtend.o *crtend?.o ) .ctors))
    KEEP (*(SORT(.ctors.*)))
    KEEP (*(.ctors))
  }

func_ptr *p;
  for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--)
    (*p) ();

void dothat() { }
struct f {
    f() { dothat(); }
} f_;
void doit() __attribute__((constructor (0)));
void doit() { }
int main() { }

.ctors          0x080494f4       0x10
 *crtbegin.o(.ctors)
 .ctors         0x080494f4        0x4 /usr/lib/gcc/i686-pc-linux-gnu/4.3.2/crtbegin.o
 *crtbegin?.o(.ctors)
 *(EXCLUDE_FILE(*crtend?.o *crtend.o) .ctors)
 .ctors         0x080494f8        0x4 /tmp/ccyzWBjs.o
 *(SORT(.ctors.*))
 .ctors.65535   0x080494fc        0x4 /tmp/ccyzWBjs.o
 *(.ctors)
 .ctors         0x08049500        0x4 /usr/lib/gcc/i686-pc-linux-gnu/4.3.2/crtend.o

E.g Mixing:  int p [] = { 1,2,3 };
          And:  extern int * p;