C语言: pointer returned by malloc() and casting

Question

Possible Duplicate:
Do I cast the result of malloc?
What is the Best Practice for malloc?

我是 C 语言新手，我有一个问题 正如我在类里面所解释的:

The type of the pointer returned by malloc() is void *, and therefore we need to cast it into the required type

这意味着我需要做:

char *str;
str = (char *) malloc(14);

但是我不明白，这是必须的吗？假设 malloc 返回 void 指针，为什么我看到许多关于而不进行转换的示例？一个例子:

float *arr = malloc (20 * sizeof (float));

有人可以解释一下吗:)？

Answer 1

在 C 中，不需要进行此强制转换。转换确实是隐式的。

C11 (n1570), § 6.3.2.3 Pointers

A pointer to void may be converted to or from a pointer to any object type. A pointer to any object type may be converted to a pointer to void and back again; the result shall compare equal to the original pointer.

由于它是不必要的，因此是否强制转换 malloc 返回是另一个问题(请参阅 here )。