полезный приемчик программерам на С

Author: Д.П. [369 views] 2012-11-26 18:49:37

Недавно открыл для себя в GNU ld (binutils) такую опцию, рекомендации лучших собаководов. Иех, и еще вопрос - почему за 15 лет существования этой опции никто мне её не подсказал? Это-то при работе в Си-конторе...

--wrap=symbol
Use a wrapper function for symbol. Any undefined reference to symbol will be resolved to __wrap_symbol. Any undefined reference to __real_symbol will be resolved to symbol.

This can be used to provide a wrapper for a system function. The wrapper function should be called __wrap_symbol. If it wishes to call the system function, it should call __real_symbol.

Here is a trivial example:

void *
__wrap_malloc (size_t c)
{
printf ("malloc called with %zu\n", c);
return __real_malloc ©;
}


If you link other code with this file using --wrap malloc, then all calls to malloc will call the function __wrap_malloc instead. The call to __real_malloc in __wrap_malloc will call the real malloc function.

You may wish to provide a __real_malloc function as well, so that links without the --wrap option will succeed. If you do this, you should not put the definition of __real_malloc in the same file as __wrap_malloc; if you do, the assembler may resolve the call before the linker has a chance to wrap it to malloc.

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