重新分配返回 null？
我用 malloc 分配了一些内存 - 大约 128 字节。
后来，我用大约 200 字节调用 realloc，但它返回 null！
如果我释放它，它会返回一个有效的指针，然后返回另一个malloc，但是我想使用realloc。
什么可以解释这种行为（我显然没有耗尽内存）？这是有效的行为吗？
代码位：
//class constructor
size = 0;
sizeAllocated = DEFAULT_BUFFER_SIZE; //64
data = (char*)malloc(sizeAllocated * sizeof(char)); //data is valid ptr now, I've checked it
data[0] = '\0';
//later on:
//append function
bool append(char** data, const char* str, size_t strLen) {
if((size + strLen) >= sizeAllocated) {
sizeAllocated += strLen + 1 + BUFFER_ALLOCATION_STEP;
char* temp = realloc(*data, sizeAllocated * sizeof(char));
if(temp)
*data = temp;
return( temp != NULL );
}
编辑：已修复。我超载了<<我的类的运算符，并让它返回 *this 而不是 void。不知怎的，这把一切都搞砸了！如果有人能解释为什么会发生这种情况，那就太好了！
I allocate some memory with malloc - about 128 bytes.
Later on, I call realloc with about 200 bytes, but it's returning null!
It returns a valid pointer if I do free, and then another malloc, however I would like to use realloc.
What could explain this behavior (I clearly am not running out of memory)? Is this valid behavior?
Code bits:
//class constructor
size = 0;
sizeAllocated = DEFAULT_BUFFER_SIZE; //64
data = (char*)malloc(sizeAllocated * sizeof(char)); //data is valid ptr now, I've checked it
data[0] = '\0';
//later on:
//append function
bool append(char** data, const char* str, size_t strLen) {
if((size + strLen) >= sizeAllocated) {
sizeAllocated += strLen + 1 + BUFFER_ALLOCATION_STEP;
char* temp = realloc(*data, sizeAllocated * sizeof(char));
if(temp)
*data = temp;
return( temp != NULL );
}
EDIT: fixed. I was overloading the << operator for my class, and had it return *this instead of void. Somehow this was screwing everything up! If anyone could explain why this happen, it would be nice!
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由于以下评论已添加到问题中
现在我们可以弄清楚发生了什么。您用一个不具有相同值的常量替换了 sizeAllocation。出于调试目的，添加一条将输出 sizeAllocation 值的语句，您会感到惊讶。
Since the following comment was added to the question
Now we can figure out what happened. You replaced sizeAllocated with a constant that DID NOT have the same value. For debugging purposes, add a statement that will output the value of sizeAllocated and you will be surprised.