When to use static keyword before global variables?

Can someone explain when you're supposed to use the static keyword before global variables or constants defined in header files? For example, lets say I have a header file with the line: const float kGameSpriteWidth = 12.0f; Should this have static in front of const or not? What are some best practices for using static ? static呈现文件的局部变量,这通常是一件好事,例如参见这个维基百科

什么时候在全局变量之前使用static关键字?

有人可以解释什么时候应该在全局变量或常量在头文件中定义之前使用static关键字吗? 例如,让我说我有一个头文件的行: const float kGameSpriteWidth = 12.0f; 应该在const前面有static吗? 什么是使用static一些最佳实践? static呈现文件的局部变量,这通常是一件好事,例如参见这个维基百科条目。 你不应该在头文件中定义全局变量。 您应该在.c源文件中定义它们。 如果全局变量仅在一个.c文件中可见,则应声明它

Using OpenMP with llvm

So I tried to use OpenMP with one of the latest version of clang, clang version 3.4.2 (tags/RELEASE_34/dot2-final) . Followed the procedure to compile and add the PATHs of omp.h , then Compiling my hello.c using : clang -fopenmp hello.c and then running it, still it can't use more than 1 threads: Bash-4.1$ ./a.out Hello from thread 0, nthreads 1 PS: I tried to manually export export OMP

使用OpenMP和llvm

所以我试着用最新版本的叮当声clang version 3.4.2 (tags/RELEASE_34/dot2-final)来使用OpenMP。 遵循该过程编译并添加omp.h ,然后使用以下命令编译我的hello.c: clang -fopenmp hello.c 然后运行它,仍然不能使用超过1个线程: Bash-4.1$ ./a.out Hello from thread 0, nthreads 1 PS:我试图手动导出export OMP_NUM_THREADS=8但这并没有解决任何问题。 有任何想法吗? 更新:这是hello.c: #include <omp.h>

In C#, how can I rethrow InnerException without losing stack trace?

I am calling, through reflection, a method which may cause an exception. How can I pass the exception to my caller without the wrapper reflection puts around it? I am rethrowing the InnerException, but this destroys the stack trace. Example code: public void test1() { // Throw an exception for testing purposes throw new ArgumentException("test1"); } void test2

在C#中,如何重新抛出InnerException而不丢失堆栈跟踪?

我通过反思调用了一种可能导致异常的方法。 如何在没有包装反射的情况下将异常传递给我的调用者? 我重新抛出InnerException,但是这破坏了堆栈跟踪。 示例代码: public void test1() { // Throw an exception for testing purposes throw new ArgumentException("test1"); } void test2() { try { MethodInfo mi = typeof(Program).GetMethod("test1");

How does a program know where the bss segment is located

As far as i have understood x86 has dedicated registers for pointers to code-, data- and stack segment, but not bss- and heap segment. How does the computer remember where these segments are? Especially heap, since bss is directly after data, but heap often is placed a different place in memory. The heap is usually created by the C runtine which is linked with your code (statically or dynamic

程序如何知道bss段的位置

据我了解,x86具有专用寄存器,用于指向代码段,数据段和堆栈段的指针,但不包括bss段和堆段。 电脑如何记住这些细分市场在哪里? 特别是堆,因为bss直接在数据之后,但堆经常放在内存中的不同位置。 堆通常由与您的代码(静态或动态)链接的C runtine创建。 它决定虚拟地址中的地址,调用操作系统提供的系统调用来映射页面,并将地址存储在由malloc(和函数族)使用的一些数据结构中。 所有这些代码要么在调用main之前执

How does malloc() know where the heap starts?

When the OS loads a process into memory it initializes the stack pointer to the virtual address it has decided where the stack should go in the process's virtual address space and program code uses this register to know where stack variables are. My question is how does malloc() know at what virtual address the heap starts at? Does the heap always exist at the end of the data segment, if so

malloc()如何知道堆的起始位置?

当OS将进程加载到内存中时,它将堆栈指针初始化为虚拟地址,它已经决定堆栈应该在进程的虚拟地址空间中的位置,程序代码使用该寄存器来知道堆栈变量的位置。 我的问题是malloc()如何知道堆的起始虚拟地址? 这个堆是否总是存在于数据段的末尾,如果是的话malloc()如何知道它在哪里? 或者它甚至是一个连续的内存区域,或者是随机散布在数据部分中的其他全局变量? malloc实现依赖于操作系统; 他们用来获取堆的开始的过

Where in memory are variables stored in c, Heap or Stack?

int main(void) { int a=10; char b[10]="HELLO"; const int x=10; return 0; } "a" will be stored in the stack only (data segment not possible) with its value(10) "b" will be stored as a pointer (because the array is a pointer to the first element) in the stack and "HELLO" will be stored in heap ( like if we are using malloc). "x" can be sto

内存中的变量存储在c,Heap或Stack中的变量中?

int main(void) { int a=10; char b[10]="HELLO"; const int x=10; return 0; } “a”将仅存储在堆栈中(数据段不可能),其值(10) “b”将作为一个指针存储(因为数组是一个指向第一个元素的指针)并且“HELLO”将被存储在堆中(就像我们使用malloc一样)。 根据编译器的不同,“x”可以存储在数据,堆栈或文本中。 如果我错了,请纠正我。 “a”将仅存储在堆栈中(数据段不可能),其值(10) 正确。 “b”

Should I make stack segment large or heap segment large?

I'm programming a design for a microprocessor with very limited memory and I must use "a lot" of memory in different functions. I can't have a large stack segment, heap segment, data segment, I must choose which to make big and which to make small. I have about 32KB total, I use about 20KB for the text segment, that gives me 12KB for the rest. And I need a buffer of 4KB to

我应该让堆栈段大还是堆段大?

我正在编程一个微处理器的设计,内存非常有限,我必须在不同的功能中使用“大量”内存。 我不能有一个大的堆栈段,堆段,数据段,我必须选择哪个做大,哪个做小。 总共约32KB, 我使用大约20KB的文本段,这给了我剩下的12KB。 我需要一个4KB的缓冲区来传递不同的功能(SPI闪存扇区大小)。 应该在哪里初始化那个大缓冲区? 所以我的选择是: 1)如果我在函数的开头声明缓冲区,堆栈将需要变大 spiflash_read(...) { u8

Multiple threads and CPU cache

I am implementing an image filtering operation in C using multiple threads and making it as optimized as possible. I have one question though: If a memory is accessed by thread-0, and concurrently if the same memory is accessed by thread-1, will it get it from the cache ? This question stems from the possibility that these two threads could be running into two different cores of the CPU. So an

多线程和CPU缓存

我使用多线程在C中实现图像过滤操作,并尽可能优化。 我有一个问题,但:如果一个内存被线程0访问,并且如果相同的内存被线程1访问,它会从缓存中获取它吗? 这个问题源于这两个线程可能运行到CPU的两个不同内核的可能性。 所以另一种说法是:所有内核都共享相同的缓存吗? 假设我有如下的内存布局 int output [100]; 假设有2个CPU核心,因此我产生了两个线程同时工作。 一种方案可能是将内存分成两个块,即0-49和50-9

How to debug nondeterministic access violation crash?

Our C#/COM/C++ application is crashing and I need help debugging it. Running with gflags enabled and WinDbg attached, we determined the crashes are caused by an access violation, but we haven't been able to narrow it down any more than that. We are not seeing the issue on all machines; there are a couple of machines that seem to reproduce the issue frequently but not deterministically. We

如何调试非确定性访问冲突崩溃?

我们的C#/ COM / C ++应用程序崩溃了,我需要帮助调试它。 运行启用了gflags和WinDbg后,我们确定崩溃是由访问冲突造成的,但我们还没有能够缩小它的范围。 我们没有看到所有机器上的问题; 有几台机器似乎经常重现这个问题,但不是确定性的。 我们观察到应用程序崩溃时,只需从应用程序切换(例如Alt-Tab),然后再切换回来。 WinDbg的输出如下。 我们一直在系统地评论可能导致问题的代码领域,但我们还没有取得太大的成

Finding where memory was last freed?

Very general: Is there an easy way to tell which line of code last freed a block of memory when an access violation occurs? Less general: My understanding of profilers is that they override the allocation and deallocation processes. If this is true, might they happen to store the line of code that last freed a section of memory so that when it later crashes because of an access violation, you

寻找上次释放内存的位置?

非常一般:有一种简单的方法可以告诉哪一行代码在发生访问冲突时最后释放了一块内存? 不那么一般:我对分析器的理解是它们会覆盖分配和释放过程。 如果这是真的,他们可能会碰巧存储最后释放一段内存的代码行,以便当它由于访问冲突而崩溃时,您知道最后释放了哪些内容? 细节: Windows,ANSI C,使用Visual Studio 是! 安装Windows调试工具并使用Application Verifier。 文件 - >添加应用程序,选择你的.exe