c - 在内存中分配特定数量的字节

Question

已关闭。这个问题是 not reproducible or was caused by typos 。目前不接受答案。

---

这个问题是由拼写错误或无法再重现的问题引起的。虽然类似的问题可能是 on-topic在这里，这个问题的解决方式不太可能帮助 future 的读者。

已关闭 7 年前。

Improve this question

我一直在尝试在内存中分配指定字节数的内存池。当我继续测试该程序时，它每次只会为每个内存池分配一个字节。

   typedef struct _POOL
{
    int size;
    void* memory;

} Pool;

Pool* allocatePool(int x);
void freePool(Pool* pool);
void store(Pool* pool, int offset, int size, void *object);

int main()
{

    printf("enter the number of bytes you want to allocate//>\n");
    int x;
    int y;
    Pool* p;
    scanf("%d", &x);
    printf("enter the number of bytes you want to allocate//>\n");
    scanf("%d", &x);
    p=allocatePool(x,y);
    return 0;

}



Pool* allocatePool(int x,int y)
{
    static Pool p;
    static Pool p2;
    p.size = x;
    p2.size=y;
    p.memory = malloc(x);
    p2.memory = malloc(y);
    printf("%p\n", &p);
    printf("%p\n", &p2);
    return &p;//return the adress of the Pool


}

Answer 1

池可以在 main 中声明，并与请求的金额一起传递给 allocatePoll 函数，然后返回。

#include <stdio.h>
#include <stdlib.h>

typedef struct _POOL
{
    size_t size;
    void* memory;
} Pool;

Pool allocatePool(Pool in, int x);
Pool freePool(Pool in);

int main()
{
    size_t x = 0;
    size_t y = 0;
    Pool p = { 0, NULL};
    Pool p2 = { 0, NULL};

    printf("enter the number of bytes you want to allocate//>\n");
    scanf ( "%zu", &x);
    p=allocatePool(p,x);
    printf("%p\n", p.memory);
    printf("enter the number of bytes you want to allocate//>\n");
    scanf("%zu", &y);
    p2=allocatePool(p2,y);
    printf("%p\n", p2.memory);

    p = freePool ( p);
    p2 = freePool ( p2);
    return 0;
}

Pool freePool(Pool in)
{
    free ( in.memory);
    in.memory = NULL;
    in.size = 0;
    return in;
}

Pool allocatePool(Pool in,size_t amount)
{
    in.size = amount;
    if ( ( in.memory = malloc(amount)) == NULL && amount != 0) {
        printf ( "Could not allocate memory\n");
        in.size = 0;
        return in;
    }
    printf("%p\n", in.memory);
    return in;//return Pool
}