GMP库提供了包装C API的大型INT C API和C ++ API。通常，您可以通过执行
mpz_t integ;
mpz_init(integ);
（请参阅）。这样做时，稍后您必须使用 mpz_clear（integ）; 释放内存。 C ++ API的 MPZ_CLASS 自动为您处理此DEADLOCATION。
现在，如果要根据现有内存初始化 mpz_t ，并且不想复制内存内容，则可以使用函数 mpz_roinit_n（）（<（<） a href =“ https://gmplib.org/manual/integer-special-functions” rel =“ nofollow noreferrer”> 5.16 Integer Special Functions ）用于 xp ：
mpz_srcptr mpz_roinit_n(mpz_t x, const mp_limb_t *xp, mp_size_t xs)
这以特殊的方式初始化 x ，因此可以用作其他MPZ函数的纯输入操作数（因此，函数名称中的 ro ）。现在， mpz_clear（integ）的文档说：
释放X所占用的空间。为所有MPZ_T调用此功能
变量与它们完成后。
我想知道 mpz_t 's是否已通过呼叫 mpz_roinit_n（）来初始化，因为它们不需要对其进行交易。
如果我正确，这也意味着 mpz_roinit_n（）无法与C ++ API的 mpz_class 一起使用，即使 mpz_class.get_mpz_t（） ，因为 mpz_class 的destructor总是试图对基础 mpz_t 进行处理，这将导致内存问题。我在这里正确吗？
The GMP library provides a big int C API and a C++ API which wraps the C API. Usually you initialize an mpz_t struct (C API) by doing
mpz_t integ;
mpz_init(integ);
(see 5.1 Initialization Functions). When doing so, you later have to free the memory with mpz_clear(integ);. The C++ API's mpz_class handles this deallocation automatically for you.
Now, if you want to initialize an mpz_t based on existing memory, and you don't want to copy the memory contents, you can use the function mpz_roinit_n() (5.16 Integer Special Functions) for a memory area pointed to by xp:
mpz_srcptr mpz_roinit_n(mpz_t x, const mp_limb_t *xp, mp_size_t xs)
This initializes x in a special way so it can be used as a read-only input operand (hence the ro in the function name) to other mpz functions. Now, the documentation of mpz_clear(integ) says this:
Free the space occupied by x. Call this function for all mpz_t
variables when you are done with them.
I wonder if mpz_t's which have been initialized with a call to mpz_roinit_n() are an exemption to this rule, because they don't need to be deallocated.
If I'm correct, this would also mean that mpz_roinit_n() can't be used with the C++ API's mpz_class, not even with mpz_class.get_mpz_t(), because mpz_class's destructor always tries to deallocate the underlying mpz_t, and this would cause memory issues. Am I correct here?
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mpz_clear对使用mpz_roinit_n设置的mpz_t不执行任何操作。所以你不需要调用它，但如果它被调用它仍然是安全的。mpz_cleardoes nothing on ampz_tset withmpz_roinit_n. So you don't need to call it, but it is still safe if it gets called.