set_new_handler例子

最新推荐文章于 2024-05-19 20:59:54 发布

转载最新推荐文章于 2024-05-19 20:59:54 发布 · 316 阅读

本文介绍了一个自定义new处理器的实现，通过安装一个new处理器来处理内存分配失败的情况，并释放预分配的安全缓冲区来尝试再次分配内存。

#include <iostream>
/// buffer to be allocated after custom new handler has been installed
char* g_pSafetyBuffer = NULL;

/// exceptional one time release of a global reserve
void my_new_handler()
{
if (g_pSafetyBuffer) {
delete [] g_pSafetyBuffer;
g_pSafetyBuffer = NULL;
std::cout << "[Free some pre-allocated memory]";
return;
}
std::cout << "[No memory to free, throw bad_alloc]";
throw std::bad_alloc();
}

/// illustrates how a custom new handler may work
int main()
{
enum { MEM_CHUNK_SIZE = 1000*1000 }; // adjust according to your system
std::set_new_handler(my_new_handler);
g_pSafetyBuffer = new char[801*MEM_CHUNK_SIZE];
try {
while (true) {
std::cout << "Trying another new... ";
new char[200*MEM_CHUNK_SIZE];
std::cout << " ...succeeded.\n";
}
} catch (const std::bad_alloc& e) {
std::cout << " ...failed.\n";
}
return 0;
}