Stack overflow

In software, a stack overflow occurs when too much memory is used on the call stack. The call stack contains a limited amount of memory, often determined at the start of the program. The size of the call stack depends on many factors, including the programming language, machine architecture, multi-threading, and amount of available memory. When a program attempts to use more space than is available on the call stack (that is, when it attempts to access memory beyond the call stack's bounds, which is essentially a buffer overflow), the stack is said to overflow, typically resulting in a program crash.

int foo() {
     return foo();
}

int foo() {
     double x[1000000];
}

递归和申请本地变量过大都容易引起栈溢出，须警惕。

Detail:Stack overflow(wiki)

举个例子：

#include <stdio.h>
int main() {
    const int stackMaxSize = 1024 * 1024 * 50;   // 50M
    char buf[stackMaxSize];
    printf("run no error!\n");
    return 0;
}

运行结果：崩溃。

bash: line 1:  1814 Segmentation fault: 11  '/Users/yuming/Downloads/test'
[Finished in 0.3s with exit code 139]

稍作修改，改为在堆上申请内存

#include <stdio.h>
int main() {
    const int stackMaxSize = 1024 * 1024 * 50;   // 50M
    char* buf = new char[stackMaxSize];
    delete []buf;
    printf("run no error!\n");
    return 0;
}

运行结果：正常。

run no error!
[Finished in 0.1s]

题外话：栈溢出漏洞很容易被入侵哦，大家小心为上。