I was reading this article and saw this: "This article assumes that you already know and understand at least basically how the memory map in GNU/Linux system works, and specially the difference between memory statically allocated in the stack and memory dynamically allocated in the heap." This confused me because I thought that stack and heap are dynamically allocated, meaning only al
我在阅读本文时看到：“本文假定您已经了解并理解GNU / Linux系统中的内存映射如何工作，特别是在堆栈中静态分配的内存与在堆。” 这使我感到困惑，因为我认为堆栈和堆是动态分配的，意味着只在必要时分配，并且在函数内声明为“静态”的全局变量和变量是静态分配的，意味着始终分配。 例如，如果我有 void f() { int x = 1; ... } 值1只能放在堆栈上，并且只有函数f（）被调用时，堆栈指针才会增加。 同样，如果我有
I was of the impression that in C#, struct elements are allocated on the stack and thus disappear when returning from a method in which they were created. But what happens if I place the struct-values in a list and return that? The elements survives. Are struct instances sometimes allocated on the heap? internal struct Stru { public int i; } internal class StruTry { public List<Stru&g
我的印象是，在C＃中，struct元素在堆栈中分配，因此从创建它们的方法返回时会消失。 但是如果我把struct-values放在一个列表中并返回，会发生什么？ 元素生存下来。 结构实例是否有时在堆上分配？ internal struct Stru { public int i; } internal class StruTry { public List<Stru> Get(int max) { var l = new List<Stru>(); for (int i = 0; i < max; i++) l.Add(new Stru {i=i});
I am stuck learning basics of assembly language with fahrenheit to celsius example from K&R book. Here is C code that I am referring to: #include <stdio.h> main() { int fahr, celsius; int lower, upper, step; lower = 0; upper = 300; step = 20; fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%dt%dn", fahr, cels
我坚持学习汇编语言的基础知识，用华氏温度对K＆R书中的摄氏例子进行学习。 这里是我所指的C代码： #include <stdio.h> main() { int fahr, celsius; int lower, upper, step; lower = 0; upper = 300; step = 20; fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%dt%dn", fahr, celsius); fahr = fahr + step; } } 随着
I created a SqlDependency so that an event would fire when the results of a particular query change. // Create a command SqlConnection conn = new SqlConnection(connectionString); string query = "SELECT MyColumn FROM MyTable;"; SqlCommand cmd = new SqlCommand(query, conn) cmd.CommandType = CommandType.Text; // Register a dependency SqlDependency dependency = new SqlDependency(cmd); dependency.On
我创建了一个SqlDependency，以便在特定查询的结果发生变化时触发事件。 // Create a command SqlConnection conn = new SqlConnection(connectionString); string query = "SELECT MyColumn FROM MyTable;"; SqlCommand cmd = new SqlCommand(query, conn) cmd.CommandType = CommandType.Text; // Register a dependency SqlDependency dependency = new SqlDependency(cmd); dependency.OnChange += DependencyOnChange;
I am currently taking an operating systems course and I am at a point where we are discussing memory portion of a process. When a program is loaded into memory and thus becomes a process, two forms of memory could be used: either a stack data structure or a heap(I am not quite sure if it's called heap because it actually uses the heap data structure). I have already looked at this link Do t
我目前正在参加一个操作系统课程，而我正在讨论流程的内存部分。 当一个程序被加载到内存中并因此成为一个进程时，可以使用两种形式的内存：一个是堆栈数据结构还是一个堆（我不太确定它是否被称为堆，因为它实际上使用了堆数据结构）。 我已经看过这个链接堆栈和堆都存在于你的系统RAM中吗？ 这在一定程度上帮助了我，但实际上并没有回答我的问题。 现在我的问题是： 堆栈是存储局部变量的内存。 当一个函数被调用时，
Why does alloca not check if it can allocate memory? From man 3 alloca : If the allocation causes stack overflow, program behavior is undefined. … There is no error indication if the stack frame cannot be extended. Why alloca does not / can not check if it can allocate more memory? The way I understand it alloca allocates memory on stack while (s)brk allocates memory on the heap. From h
为什么alloca不检查它是否可以分配内存？ 从man 3 alloca ： 如果分配导致堆栈溢出，则程序行为未定义。 ...如果堆栈帧无法扩展，则没有错误指示。 为什么alloca不能/不能检查它是否可以分配更多内存？ 我理解它的方式alloca在堆栈上分配内存，而(s)brk在堆上分配内存。 从https://en.wikipedia.org/wiki/Data_segment#Heap： 堆区由malloc，calloc，realloc和free管理，可以使用brk和sbrk系统调用来调整其大小 从
I was curious about what exactly a pointer holds, after malloc() was used to allocate memory space? The manpage tells me that calloc() initializes the allocated memory space with zero. The malloc() function allocates size bytes and returns a pointer to the allocated memory. The memory is not initialized . If size is 0, then malloc() returns either NULL, or a unique pointer value that can lat
在malloc()用于分配内存空间之后，我很好奇指针究竟保存了什么？ 手册页告诉我calloc()用零初始化分配的内存空间。 malloc（）函数分配大小字节并返回指向已分配内存的指针。 内存未初始化 。 如果size为0，则malloc（）返回NULL或一个唯一的指针值，以后可以成功传递给free（）。 和 calloc（）函数为每个大小为字节的nmemb元素的数组分配内存，并返回指向分配内存的指针。 内存设置为零 。 如果nmemb或者size是0，
I am new in CS world.While reading some books i checked that dynamic allocation of memory, allocates memory dynamically while program runs and that memory is called heap.So that means whenever i want to create a new node in Linkedlist it get stored on heap? or else it get stored on memory and accessed runtime? And i also checked that whenever any programs ran, the OS creates PCB for the same i
我在CS世界是新的。在阅读一些书籍时，我检查了内存的动态分配，在程序运行时动态地分配内存，并将内存称为堆栈。这意味着每当我想在Linkedlist中创建一个新节点时，它都会存储在堆中？ 否则它会被存储在内存中并访问运行时？ 而且我也检查过，无论何时运行任何程序，操作系统都会创建相同的PCB，包括以下最少4个部分： 堆段 堆栈段 数据段 代码段 堆段和堆段的增长动态取决于代码（向上或向下取决于系统）。 所
Reading Martin Sustrick's blog on challenges attendant with preventing "undefined behavior" in C++, vs C, in particular the problem attendant with malloc() failing due to memory exhaustion, I was reminded of the many, many times I have been frustrated to know what to do in such cases. With virtual systems such conditions are rare, but on embedded platforms, or where performance de
阅读Martin Sustrick关于在C ++和C中防止“未定义行为”的挑战的博客，特别是由于内存耗尽而导致malloc（）失败的问题时，我想起了很多很多次，我很沮丧地知道在这种情况下做。 对于虚拟系统而言，这种情况很少见，但在嵌入式平台上，或者与虚拟系统相关的性能下降等同于失败的情况下，正如Martin对ZeroMQ的情况一样，我决心找到一个可行的解决方案，并且做到了。 我想询问StackOverflow的读者是否尝试了这种方法，以及他们的
I am quite confused how memory allocation (malloc/calloc) works in linux/c. Suppose, I have a machine with 16GB RAM and I run a program as root. It is 64-bit machine, so all 16GB can be addressed as a single segment. Can I allocate all of that (less the amount for OS of course) with a single malloc call? with many malloc calls? How it all relates to "heap memory" and "virtual
我很困惑内存分配（malloc / calloc）如何在linux / c中工作。 假设，我有一台拥有16GB RAM的机器，我以root身份运行一个程序。 它是64位机器，因此所有16GB都可以作为一个单独的网段寻址。 我可以通过一次malloc调用来分配所有这些（减少操作系统的数量）吗？ 有很多malloc调用？ 这与“堆内存”和“虚拟内存”有什么关系？ 如果我分配一个小内存块，它发生在堆内存中，那么我调整（放大）这个块，当我接近堆栈区时会发生什