GlobalAlloc已经不提倡使用为了与16位的程序兼容而保留的,new是一个操作符,用来在free store 分配内存块,在windows的CRT实现中,new 操作符通常会先在进程所在的默认堆中分配内存调用顺序好像是(new(....)->malloc(....)->HeapAlloc(...))最终还是调用windowsAPI的所谓heap 函数来分配内存
网上找到的英文解释如下:
Both the malloc() and the calloc() functions are used to allocate dynamic memory. Each operates slightly different from the other.
Both the malloc() and the calloc() functions are used to allocate dynamic memory. Each operates slightly different from the other. malloc() takes a size and returns a pointer to a chunk of memory at least that big:
void *malloc( size_t size );
calloc() takes a number of elements, and the size of each, and returns a pointer to a chunk of memory
at least big enough to hold them all:
void *calloc( size_t numElements, size_t sizeOfElement );
There are one major difference and one minor difference between the two functions. The major difference is that malloc() doesn't initialize the allocated memory. The first time malloc() gives you a particular chunk of memory, the memory might be full of zeros. If memory has been allocated, freed, and reallocated, it probably has whatever junk was left in it. That means, unfortunately, that a program might run in simple cases (when memory is never reallocated) but break when used harder (and when memory is reused). calloc() fills the allocated memory with all zero bits. That means that anything there you are going to use as a char or an int of any length, signed or unsigned, is guaranteed to be zero. Anything you are going to use as a pointer is set to all zero bits.
That is usually a null pointer, but it is not guaranteed.Anything you are going to use as a float or double is set to all zero bits; that is a floating-point zero on some types of machines, but not on all.
The minor difference between the two is that calloc() returns an array of objects; malloc() returns one object. Some people use calloc() to make clear that they want an array.
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