1. Size
2. Nm
3. Readelf
4. Attribute of the Function
以下是常用的几个attribute
a) __attribute__ format
The format attribute specifies that a function takes printf, scanf stylearguments which should be type-checked against a format string. For example,the declaration:
extern int
my_printf (void*my_object, const char *my_format, ...)
__attribute__((format (printf, 2, 3)));
causes the compiler to check the arguments in callsto my_printf for consistency with the printf style formatstring argument my_format.
b) __attribute__ noreturn
The noreturn keyword tells the compiler to assumethat function cannot return.
extern void exitnow() __attribute__((noreturn));
c) __attribute__ const
d) __attribute__ weak
The weak attribute causes the declaration to be emitted asa weak symbol rather than a global. This is primarily useful in defininglibrary functions which can be overridden in user code, though it can also beused with non-function declarations.
e) __attribute__ constructor
The constructor attribute causes the function to be calledautomatically before execution enters main ().
f) __attribute__ destructor
The destructor attribute causes the function to be calledautomatically after main () has completed or exit () hasbeen called.
extern void die(const char *format, ...)
__attribute__((noreturn))
__attribute__((format(printf, 1, 2)));
/*or*/
extern void die(const char *format, ...)
__attribute__((noreturn, format(printf, 1, 2)));
g) __attribute__ alias
定义别名, 可以定义一个函数的别名, 如下可以使用函数fsl_memset代替glibc中的函数memset,
void * memset(void *dst, int val, size_t n) __attribute__((alias ("fsl_memset")));
http://gcc.gnu.org/onlinedocs/gcc-4.0.0/gcc/Function-Attributes.html
https://gcc.gnu.org/onlinedocs/gcc-4.0.0/gcc/
https://gcc.gnu.org/onlinedocs/gcc-4.0.0/gcc/Variable-Attributes.html#Variable-Attributes
5.