在C中重新分配vs malloc [英] realloc vs malloc in C

问题描述

我对C语言还很陌生，现在刚开始涉足动态分配数组的领域.

I'm fairly new to C, and just now starting to venture into the realm of dynamically allocated arrays.

我认为我大多数情况下是 malloc ，但是对 realloc 有一些疑问:

I think i've got mostly malloc down, but had some questions on realloc:

1. 除了向指针添加内存空间之外， realloc 还能用于其他任何用途吗?
2. size变量是否总是必须为 int ?

3. 是否可以进行以下工作?

1. Can realloc be used for anything else besides adding memory space to pointers?
2. Does the size variable always have to be an int?

3. Would something like the below work?

float *L = NULL;

int task_count = 5;

L = (float*) realloc (L, task_count * sizeof(float));

如果我想进一步增加该空间(在这种情况下增加一倍)，是否可以使用如下所示的内容?

If I wanted to increase that space further (by one in this case), could I just use something like the following?

L = (float*) realloc (L, 1 * sizeof(float));

看似简单，这告诉我我可能丢失了一些东西.

Seems deceptively simple, which tells me I'm possibly missing something.

推荐答案

如果ptr是空指针，则该函数的行为类似于malloc，分配一个新的大小为字节的块，并返回一个指向其开头的指针.

In case that ptr is a null pointer, the function behaves like malloc, assigning a new block of size bytes and returning a pointer to its beginning.

void * realloc (void* ptr, size_t size);

ptr-指向先前分配有malloc，calloc或 realloc 的内存块的指针.或者，它可以是一个空指针，在这种情况下，将分配一个新块(就像malloc被调用).

ptr - Pointer to a memory block previously allocated with malloc, calloc or realloc. Alternatively, this can be a null pointer, in which case a new block is allocated (as if malloc was called).

sizeNew-内存块的大小，以字节为单位.size_t是无符号整数类型.

sizeNew - size for the memory block, in bytes. size_t is an unsigned integral type.

sizeNew必须定义您想要的整个内存，可以更小，也可以更大！

sizeNew has to define the entirety of the memory you want, could be smaller, could be larger!

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