c语言第6章：内存管理

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李延 LV6 2022-05-23

悬赏：20积分

# 1 说明

简单封装malloc 方法，对于内存分配异常时，抛出异常。

# 2 mem.h

```c
#ifndef MEM_INCLUDED
#define MEM_INCLUDED

#include "../except/except.h"

extern Exception Mem_Failed;

extern void *mem_alloc(long  nbytes, const char *file, int line);
extern  void *mem_calloc(long  count,long nbytes,const char *file,int line);
extern  void mem_free(void *ptr,const char *file,int line);
extern  void mem_resize(void *ptr,long  count,const char *file,int line);

#define ALLOC(nbytes) \
mem_alloc(nbytes,__FILE__,__LINE__)

#define CALLOC(count,nbytes) \
mem_calloc(count,nbytes,__FILE__,__LINE__)

#define FREE(ptr) \
mem_free(ptr,__FILE__,__LINE__)
#define RESIZE(ptr,count) \
mem_resize(ptr,count,__FILE__,__LINE__)

#define NEW(p) ((p) = ALLOC((long) sizeof *(p)))
#define NEW0(p) ((p) = CALLOC(1,(long) sizeof *(p)))

#endif
```

# 3 mem.c

```c
#include "mem.h"
#include "stdlib.h"

Exception Mem_Failed = {"Allocation Failed"};
static void throw_error(Exception *exception, const char *file, int line) {
    if (file == NULL) {
        Throw(&Mem_Failed);
    } else {
        throwFunction(&Mem_Failed, file, line);
    }
}

void *mem_alloc(long nbytes, const char *file, int line) {
    void *ptr;
    assert(nbytes > 0);
    ptr = malloc(nbytes);
    if (ptr == NULL) {
        throw_error(&Mem_Failed, file, line);
    }
    return ptr;
}

void *mem_calloc(long count, long nbytes, const char *file, int line) {

assert(count >0);
    assert(nbytes >0);
    void *ptr = calloc(count, nbytes);
    if(ptr == NULL){
        throwFunction(&Mem_Failed, file, line);
    }
    return ptr;
}

void mem_free(void *ptr,const char *file,int line){
    if(ptr){
        free(ptr);
    }
}

void mem_resize(void *ptr,long  count,const char *file,int line){
    assert(ptr);
    assert(count >0);
    ptr = realloc(ptr,count);
    if(ptr == NULL){
        throwFunction(&Mem_Failed, file, line);
    }
}
```

# 4 测试

```c
#include "../mem/mem.h"
#include "stdio.h"

int main() {

int *p;
    NEW(p);
    *p = 3;
    printf("%d\n", *p);
    FREE(p);
    printf("%d\n", *p);

}
```

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