用C/C++程序控制环境变量
In C++, how do i go about using setenv to set the display? I need to set it like this:
export DISPLAY=0.0
1、setenv("DISPLAY",":0.1",1);
If you're calling the xrandr functions from your C++ program, then I would expect setenv() should work for you. The 3rd argument of 1 tells setenv() to overwrite any previous value of argument 1 (DISPLAY). You'd be out of luck if xrandr cached the display name though. In that case, you'd have to re-invoke a program from a shell script: the shell script could set the DISPLAY each time before starting your program. That would be less C++ coding
#include <stdlib.h>
#include <stdio.h>
int main(){
char *env1 = getenv("test11");
printf("test11=%s\n", env1); //show current env variable
setenv("test11","abcd",1); //reset it
env1 = getenv("test11");
printf("test11=%s\n", env1);
//this value reset is gone after the program finished
return 0;
}
g++ setenv.cpp -o mysetenv
相关文档：
设置：
1. Tools/Projects and Solutions/VC ++ Directories
Inlcude files: C:\Program Files\MATLAB\R2009a\extern\include
Library files: C:\Program Files\MATLAB\R2009a\extern\lib
2. Property
Configuration Properties/Linker
......
网上搜索了一大堆去掉/*和*/之间注释的代码,就像<The C Programming Language>练习1-23里有人说的一样
大部分都会被以下的程序broken,这个功能看起来简单,实际上很有难度.网上实现的代码,除了我找到的一个用文件指针实现的没有问题外,其余的都存在各种bug,不信的话就用以下的程序测试一下:-),当然这个程序也不够完善 ......
1.求下面函数的返回值（ 微软）
int func(x)
{
int countx = 0;
while(x)
{
countx ++;
x = x&(x-1);
......
这段源码能在linux下运行！！！ 能识别小数
#include<unistd.h>
#include<stdlib.h>
#include<stdio.h>
#include<string.h>
/*#define NULL 0*/
/* 自定义变量 */
#define&n ......
int svd(int m,int n,int withu,int withv,double eps,double tol,
double *a, double *q, double *u, double *v, double *vt)
{
int i,j,k,l,l1,iter,retval;
double c,f,g,h,s,x,y,z;
double *e;
e = (double *)calloc(n,sizeof(double));
retval = 0;
/* Cop ......
