local or global array variable alignment
2017-10-6
我们经常会定义一个char数组作为缓存接收数据,然后将接收的数据转换为某一个结构体。这里通常要求数组按照结构体的要求对齐。那么默认的cha数组是对齐到多少呢?1还是?如果为1的话,意味着我们要显示地给出对齐要求。查到的资料是,局部或全局数组如果大于16个字节会对齐到16字节。https://stac
volatile struct semantics
2017-10-15
https://stackoverflow.com/questions/2044565/volatile-struct-semantics In your example, the two are the same. But the issues revolve around pointers.Fi
c array and pointer
2019-5-7
123456789101112int a[10];int *b;int (*c)[10];int d;int e[10][2];int (*f)[2]; b = a;b = &a[0];c = &a;d = a[2];f = e;直接使用数组,等价于取数组首元素的地址。a等价于&a[0]。#incl
C类型转换
2025-2-20
Implicit type castingC支持隐式转换:12short a = 10;int b = a;Explicit type casting显示转换:1234567891011 signed char a = -1; unsigned char b = -1;
memmem未声明导致返回值不对的问题分析
2019-10-28
在64位系统上,使用memmem接口,根据手册,memmem声明在string.h代码如下:#include #include #include #define _GNU_SOURCE#include main(){
stardard io buffer机制
2019-10-28
标准输入输出库,有3种类型的bufferunbuffered,立即输出。block buffered,缓存满输出。line buffered,按行输出。通常,所有的文件都是block buffered。如果一个stream指向一个terminal,它是line buffered。标准错误默认总是un
Compound literals
2020-2-10
可以认为等价于匿名数组或者匿名结构体变量。来看它的一个例子: struct proto **proto = (struct proto* []) { & ctx->lan, & ctx->wan, 0, }; while (*pr
Automatic (auto) variables in c language
2021-2-1
自动变量就是局部变量,他们的内存是自动分配的,自动释放的。The variables which are declared inside a block are known as automatic or local variables; these variables allocates memo
Short-circuit evaluation
2021-2-2
Short-circuit evaluation, minimal evaluation, or McCarthy evaluation (after John McCarthy) is the semantics of some Boolean operators in some programm
C escape sequences
2022-1-12
只支持下列转义序列newline\nbackslash\\horizontal tab\tquestion mark\?vertical tab\vsingle quote\'backsapce\bdouble quote\"carriage return\roctal number\oooform
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