gcc extension __attribute__ meanings <p>when I look some code, I find the following snap.</p> <pre><code>void ph_library_init_register(struct ph_library_init_entry *ent); #define PH_LIBRARY_INIT_PRI(initfn, finifn, pri) \ static __attribute__((constructor)) \ void ph_defs_gen_symbol(ph__lib__init__)(void) { \ static struct ph_library_init_entry ent = { \ __FILE__, __LINE__, pri, initfn, finifn, 0 \ }; \ ph_library_init_register(&amp;ent); \ } </code></pre> <p>my question is: 1. what is <strong>stribute</strong> means? 2. when does the code run?</p>