daa20的专栏

C语言注册函数和调用函数。见：haproxy代码。

queue.h:/* * List definitions. */#define LIST_HEAD(name, type) \struct name { \ struct type *lh_first; /* first element */

$ cat test.c#include <stdio.h>#include <string.h>int run_and_get_output(const char* cmd, char *output, int max_len){ char buffer[1000] = {0}; int len = 0; int copy_len = 0; FILE *pipe = NULL; pipe = popen(cmd, "r");

struct 变量高效赋值的一个例子：# cat test.c#include <stdio.h>#include <stdlib.h>typedef struct _tag_t_{ int i; int j;} t_t;typedef struct _tag_tst_{ int a; int b; t_t t;} tst_t;void func(void){ tst_t *tst1 = NULL;

https://blog.youkuaiyun.com/weixin_34267123/article/details/85733011

转自：https://www.cnblogs.com/qcloud1001/p/9585724.html在x86-64下使用RDTSC指令，直接从寄存器读取，需要输入2个参数，比较常见的实现：static inline uint64_trte_rdtsc(void){uint32_t lo, hi; __asm__ __volatile__ ( "rdtsc" : "=a"(lo), "=d"(hi) ); return ((unsig

1、加载动态库：(1) gdb ./a.out coredump(2)set solib-search-path ./lib(3)bt2、addr2line的使用：# addr2line --helpUsage: addr2line [option(s)] [addr(s)] Convert addresses into line number/file name pairs. If ...

出自：lex和yacc（第二版）例子，文件1：[root@localhost ~/test/flex_bison/flex/ch1-05]# cat test1.l%{#include <stdio.h>#include <stdlib.h>#include <string.h>#include "test1.tab.h"#define L...

学习《lex与yacc（第2版）》时，根据第一章节04小结，重写了如下用例，用于理解和加深对flex的掌握。# cat test1.l%{/*symbol table to recognize words */enum { LOOKUP = 0, VERB, ADJ, ADV, NOUN, PREP, PRON, CONJ}...

# cat test.c #include <stdio.h>#include <stdint.h>voidfunc_1(void){ uint32_t mask = 0xFFFFFFFF; uint32_t masklen = 0; printf("mask: %x\n", (mask << (32 - masklen))...

1 #include <stdio.h> 2 #include <stdlib.h> 3 #include <assert.h> 4 #include <string.h> 5 6 typedef struct _tst_t { 7 int a; ...

问题描述：发送压缩文件到qq邮箱，发现标题为中文名称，能正常显示，但是附件的中文名称为乱码。任务：解决附件中文名称的乱码问题。前期资料总结：1、SMTP乱码解决方案（源自https://blog.youkuaiyun.com/saokeliu/article/details/5194547）Smtp发送中文邮件的时候也会产生像ftp乱码的现象，不知道在网上这样的资料很少，让我们那些第一次遇到这种问题的...

#include #include int func();int main(){ printf("[%s,%d] this is main!\n",__FILE__,__LINE__); func(); return 0;}// ...#line 1 "QG-Copy Right"int func(){ printf("Hi,this is QG

方法1、（1）先获取进程的PIDps -aux | grep test# ps -aux | grep testroot 6906 85.7 0.0 4212 356 pts/0 R+ 00:56 3:57 ./testroot 6978 0.0 0.0 112708 980 pts/1 R+ 01:01 0:00 g...

https://www.cnblogs.com/lonelycatcher/archive/2011/10/09/2204865.html例子：[root@localhost ~/test/test_2]# cat -n test.c 1 #include <stdio.h> 2 3 int 4 main(int argc, cha...

source insight 3.51.设置字体大小options-document options ，找到screen fonts，即可打开字体设置界面设置全文字体大小2.往里添加中文注释或英文注释时，字间距很大。解决方法如下： （1）、Options->Style Properties （2）、左边Style Name下找到Comment Multi Line、Com...

一种原因是：多次free造成的。

转自：http://androider.iteye.com/blog/1423847 git-svn用法博客分类： Version Control检出一个已存在svn repository(类似于svn checkout) 我们可以通过git-svn clone命令完成这个操作： git-svn clone your_svn_repository_url从中心服务器的svn reposito

如果str在堆中申请的空间较小，使用scanf(“%s”,str)时，很容易发生溢出，怎么解决呢？？？#include <stdio.h>#include <malloc.h>int main(int argc, char *argv[]){ char *str = (char *)malloc(10 * sizeof(char)); printf("please input(1

#include #include /* run this program using the console pauser or add your own getch, system("pause") or input loop */#define RESET(p,len) while(len>0) ((char*)p)[--len]=0void reset(void* p,in

#include #include /* run this program using the console pauser or add your own getch, system("pause") or input loop */int main(int argc, char *argv[]){ char* p; if((p=(char*)malloc(0))==NULL)

#include #include #include struct Student{ char* name; int age; };int main(int argc,char* argv[]){ struct Student s; //s.name = (char*)malloc(sizeof(char)*20); //少了这句，就会使s.name变成野指针

#include #include #include //malloc()#include // memset()/* run this program using the console pauser or add your own getch, system("pause") or input loop *///-----------------------------

#include #include /* run this program using the console pauser or add your own getch, system("pause") or input loop */int main(int argc, char *argv[]) { int a[5] = {0,1,2,3,4}; int* p = a;

#include #include #include void test_1(){ int i = 2; int *p = &i; printf("%d, %08x\n",i,p); *p =10; printf("%d, %08x\n",i,&p);}void test_2(){ int* pI; char* pC; long* pL; double* pD

#include #define Variable(x) #x#define NAME(n) name##n#define STRUCT(type) typedef struct _tag_##type type; \struct _tag_##typeSTRUCT(Student){ int ID; char* name;};void test_1(){

#include #include #pragma pack(4) //default value#if defined(ANDROID2_0) #pragma message("android-2.0") //only VS surpose #define VERSION "android 2.0"#elif defined(ANDROID4_0) #

#include #include /* run this program using the console pauser or add your own getch, system("pause") or input loop */#define HI "hi,I am OK!"int main(int argc, char *argv[]) { #ifndef COMMAND

//#和#line的使用 #include #define convert(x) #x //very good#define print(func,x) (printf("the %s ",#func),func(x)) //very goodint SUM(int x){ int ret; if

如：int  a = 10;int* pt = &a;指针是对普通变量的操作；等同与：int* a = 10;int** pt = &a;二级指针是对指针的操作。void test(){ int a = 10; int* pt = &a; int** ppt = &pt; cout << "a = " << a << endl;

//--------------实现加一秒后年月日时分秒的显示----------------struct _tag_data{ unsigned int year; unsigned char month; unsigned char day; unsigned char hour; unsigned char minute; unsigned char second; }

#include #include #include #include /* run this program using the console pauser or add your own getch, system("pause") or input loop */void test_1(){ int const a = 2; const int b = 3; int

#include #include /* run this program using the console pauser or add your own getch, system("pause") or input loop *///strcmp函数的实现，匹配成功返回0。否则返回-1int myStrcmp(const char* src,const char* dest){

DEV-C编辑器结果： printf("---------------------------------\n"); const int* ip = &a; //常量指针，，地址可变 //*ip = b; //[Error] assignment of read-only location '*ip' ip = &b; printf("------------

#include #include /* run this program using the console pauser or add your own getch, system("pause") or input loop */int f(int n){ int ret = 0; if(n>1) { ret = n*f(n-1); } else if(n==1)

/*数组指针的使用*/#include <stdio.h>typedef int(AINT5)[5]; //数组类型为:int[5]typedef char(ACHAR2)[2];void test_1(){ AINT5 a; //等同于 int a[5] AINT5* a1 = &a; //等同于 int (*a1)[5] int i=0; printf(

#include <stdio.h>#include <malloc.h>typedef unsigned char u8; typedef unsigned short u16;typedef unsigned int u32;typedef struct _tag_Test1{ u32 a; u8 b; u8 c;

作者：feilengcui008链接：http://www.zhihu.com/question/31855632/answer/54747429来源：知乎著作权归作者所有，转载请联系作者获得授权。#include <stdio.h>int max(const int &a, const int &b){ return a>b ? a : b;}int min(const int

#include <stdio.h>#include <assert.h>#include <malloc.h>char* myStrcpy(char* dst,const char* src){ char* ret = dst; assert(dst&&src);//安全编程策略，一定要写这一句代码，确保dst和src都不为空 while((*dst++ = *src

#include <stdio.h>size_t myStrlen(const char* s){ size_t length = 0; while(*s++) //遇到\0就返回 { length++; } return length;}int main(void){ char* s1 = "hello"; char*