Ciao pitt921,
il parametro passato al linker serve ad aggiungere tutti i simboli e non solo quelli così detti `statici` all'oggetto. E' utilizzabile forse nel contesto della libreria sharata caricata run-time, quello che comunemente chiamiamo plugin.
Puoi comunque sperimentare, osservendo le informazioni dell'oggetto, dopo la fase di link attraverso il comando di sistema `objdump`
In C (POSIX.1-2001) l'apertura/chiusura della libreria sharata viene fatto attaverso queste funzioni:
void *dlopen(const char *filename, int flag);
void *dlsym(void *handle, const char *symbol);
int dlclose(void *handle);
Manualistica ed esempi:
$man 3 dlopen
Manuale linker (ld):
$man ld
Estratto dal manuale
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-E
--export-dynamic
--no-export-dynamic
When creating a dynamically linked executable, using the -E option or the --export-dynamic option causes the linker to add all symbols to the dynamic symbol table. The dynamic symbol table is the set of symbols which are visible from dynamic objects at run time.
If you do not use either of these options (or use the --no-export-dynamic option to restore the default behavior), the dynamic symbol table will normally contain only those symbols which are referenced by some dynamic object mentioned in the link.
If you use "dlopen" to load a dynamic object which needs to refer back to the symbols defined by the program, rather than some other dynamic object, then you will probably need to use this option when linking the program itself.
You can also use the dynamic list to control what symbols should be added to the dynamic symbol table if the output format supports it. See the description of --dynamic-list.
Note that this option is specific to ELF targeted ports. PE targets support a similar function to export all symbols from a DLL or EXE; see the description of --export-all-symbols below.
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