glibc-2.9/include/libc-symbols.h 中 490 行后面的东西怎么理解？ 感觉有点儿意思，有时间再看！
如：
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/* The following macros are used for PLT bypassing within libc.so (and if needed other libraries similarly). First of all, you need to have the function prototyped somewhere, say in foo/foo.h: int foo (int __bar); If calls to foo within libc.so should always go to foo defined in libc.so, then in include/foo.h you add: libc_hidden_proto (foo) line and after the foo function definition: int foo (int __bar) { return __bar; } libc_hidden_def (foo) or int foo (int __bar) { return __bar; } libc_hidden_weak (foo) Similarly for global data. If references to foo within libc.so should always go to foo defined in libc.so, then in include/foo.h you add: libc_hidden_proto (foo) line and after foo's definition: int foo = INITIAL_FOO_VALUE; libc_hidden_data_def (foo) or int foo = INITIAL_FOO_VALUE; libc_hidden_data_weak (foo) If foo is normally just an alias (strong or weak) to some other function, you should use the normal strong_alias first, then add libc_hidden_def or libc_hidden_weak: int baz (int __bar) { return __bar; } strong_alias (baz, foo) libc_hidden_weak (foo) If the function should be internal to multiple objects, say ld.so and libc.so, the best way is to use: #if !defined NOT_IN_libc || defined IS_IN_rtld hidden_proto (foo) #endif in include/foo.h and the normal macros at all function definitions depending on what DSO they belong to. If versioned_symbol macro is used to define foo, libc_hidden_ver macro should be used, as in: int __real_foo (int __bar) { return __bar; } versioned_symbol (libc, __real_foo, foo, GLIBC_2_1); libc_hidden_ver (__real_foo, foo) */ |