dynamically allocated memory after program termination
When a C/C++ program containing the dynamically allocated memory(using malloc/new) without free/delete calls is terminated, what happens to that dynamically allocated memory? Does the operating system takes back the memory or does that memory becomes unaccessible to other programs?
I don't think that there are any guarantees in the language standard, but modern operating systems which support sparse virtual memory and memory protection (such as MacOS X, Linux, all recent version of Windows, and all currently manufactured phone handsets) automatically clean up after badly-behaved processes (when they terminate) and free the memory for you. The memory remains unavailable, however as long as the program is running.
If you're programming on microcontrollers, on MacOS 9 or earler, DOS, or Windows 3.x, then you might need to be concerned about memory leaks making memory permenantly unavailable to the whole operating system.
Most modern operating systems employ a memory manager, and all userland processes only see so-called virtual memory, which is not related to actual system memory in a way that the program could inspect. This means that programs cannot simply read another process's memory or kernel memory. It also means that the memory manager will completely "free" all memory that has been assigned to a process when that process terminates, so that memory leaks within the program do not usually "affect" the rest of the system (other than perhaps forcing a huge amount of disk swapping and perhaps some "out of memory" behaviour).
This doesn't mean that it's in any way OK to treat memory leaks light-heartedly, it only means that no single program can casually corrupt other processes on modern multi-tasking operating systems (deliberate abuse of administrative privileges notwithstanding, of course).
Short answer: yes, the OS will free this memory.
Most operating systems will free this memory, however it is bad practice to rely upon this behaviour. Some operating systems will not free this memory. For example, embedded systems. For portability, always free all the memory you allocate.
链接地址: http://www.djcxy.com/p/78716.html上一篇: 在流行的实现中，动态内存分配在C和C ++中有所不同？
下一篇: 程序终止后动态分配内存