I do think having a the reason why you would want to do this instead of
'how can I do this' might help... (something of an X-Y problem)
I can certainly generate things that run code for initialization.
On Tue, Jan 7, 2020 at 12:09 PM William Tambe <tambewilliam@xxxxxxxxx>
wrote:
> Given the following code example:
>
> void myfunc (void) {}
> void(*)(void) initmyfunc(void) {return myfunc; }
> void *myglobal = initmyfunc();
void main (void) {
> return;
> }
>
as c++...
otherwise in C, no, without attribute constructor, or, attribute seg, and
doing something to process a custom segment of initializers...
I write a macro like
#define PRELOAD(name) \
void name##__LINE__(void) __attribute__((constructor)); \
void name(void)
PRELOAD( someUniqueName ) {
/* some init that gets run */
}
could even refit it more like...
#define PRELOAD(name) \
name(void) __attribute__((constructor)); \
void name
void PRELOAD( someUniqueName ) (void) {
/* some init that gets run */
}
But really, I recall all of that was mentioned before... maybe without
specific examples...
The actual thing I do for pre-main init is the constructor functions just
call a registration of some other fucntion at some priority....
https://github.com/d3x0r/SACK/blob/master/include/deadstart.h#L507-L514
Constructor atttribute in C++ actually has a priority available too....
Is there a way to make GCC initialize global variable using
> instructions instead of assembly directive such as .long or .quad ?
> Such that in the above example the address of myfunc that is used to
> initialize myglobal get computed at run-time instead of at compile
> time.
>
