On 11/25/2009 06:24 PM, yunfeng zhang wrote:
It seems that original limitation isn't clear or sufficient
For a sample:
// f.c
int g;
void foo(void)
{
g = 1;
}
compile with `gcc -shared -fPIC -Wl,-soname,f.so,-Map,f.map -o f.so f.c'...
With -fPIC, the variable G may be overridden by another variable of the
same name from another shared object earlier in the search path. That
is, the offset is *not* fixed because the final address of G may reside
in a different .so file.
Change your program to
static int g;
or
extern int g __attribute__((visibility("hidden")));
int g;
and compare the results. In either case G is known to resolve to the
instance present in f.so. In either case we'll use a constant offset.
You really need to understand how ELF actually works before suggesting
that it's broken.
r~
