C++ how to delete a structure?
Structure I created:
struct VideoSample
{
const 开发者_如何学Pythonunsigned char * buffer;
int len;
};
VideoSample * newVideoSample = new VideoSample;
newVideoSample->buffer = buf;
newVideoSample->len = size;
//...
How now to delete it now?
delete newVideSample;
This won't free any memory you allocated to newVideoSample->buffer
though - you have to free it explicitly before deleting.
//Free newVideSample->buffer if it was allocated using malloc
free((void*)(newVideSample->buffer));
//if it was created with new, use `delete` to free it
delete newVideSample->buffer;
//Now you can safely delete without leaking any memory
delete newVideSample;
Normally this kind of freeing is written in the destructor of the class so that it'll be called automatically when you delete
the dynamically created object.
Thanks @steve for mentioning it :)
delete newVideoSample;
But if the new
and delete
are in the same context, you're probably better off skipping them and just creating it on the stack instead:
VideoSample newVideoSample = {buf, size};
In that case, no cleanup is necessary.
You're looking for the delete
keyword:
delete newVideoSample;
delete newVideoSample;
However, consider using a smart pointer that will release the memory automatically, for example:
std::auto_ptr<VideoSample> newVideoSample(new VideoSample);
In C++ a structure is the exact same as a class except everything is public by default, where a class is private by default. So a structure can have a destructor and is freed with delete.
Unless I'm missing something, you just use delete
:
delete newVideoSample;
delete newVideoSample
.
In C++ struct
is the same as class
but with default public fields.
Use delete
VideoSample * newVideoSample = new VideoSample;
//.. stuffs
delete newVideoSample;
There is also an overload i.e delete[]
VideoSample * newVideoSample = new VideoSample[n];
//.. stuffs
delete [] newVideoSample;
In Modern C++ it is always recommended to use smart pointers. You may want to use boost::shared_ptr<T>
from the boost library.
If you intended VideoSample to free its buffer
member then VideoSample is a fragile class. It has no way of knowing whether buf
was created in the heap using new[]
or malloc
, or is the address of a variable on the stack.
You created an object of Videosample
, so you just need to use use delete..
VideoSample * newVideoSample = new VideoSample;
delete newVideoSample;
To Allocate -> VideoSample * newVideoSample = new VideoSample;
To Delete -> delete newVideoSample;
If you deleting the object in the same context, you better just allocate it on the stack. If you deleting it outside the context don't forget to pass a reference.
And most important, don't delete if your about to exit process, it's pointless :P
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