Linux进程内存管理

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Linux进程内存管理

1.程序的结构与进程结构

$ size test

text data bss dec hex filename
181617 432 18844 200893 310bd ./book

一个可执行程序包括三个部分
代码段:存放指令,操作以及只读的常量
数据段:全局或者静态的已经初始化的变量
BSS段 :全局或者静态的未初始化的变量

2.进程管理的过程

在执行程序时,系统首先在内核空间中创建一个进程,为这个进程申请一个PCB (进程控制块task_struct),用于管理整个进程的所有资源,其中mm_struct成员用来管理与当前进程相关的所有内存资源.

(1)代码段,数据段,BSS段,直接从磁盘拷贝到当前内存空间,大小相等.
(2)动态的空间:堆,栈空间,mmap段(用于映射其他的库的相关信息)

$ cat /proc/7450/maps
08048000-08152000 r-xp 00000000 08:01 36175926   /bin/bash
08152000-08153000 r--p 00109000 08:01 36175926   /bin/bash
08153000-08158000 rw-p 0010a000 08:01 36175926   /bin/bash
08158000-0815d000 rw-p 00000000 00:00 0 
084cf000-08994000 rw-p 00000000 00:00 0          [heap]
b710d000-b7118000 r-xp 00000000 08:01 21496849   /lib/i386-linux-gnu/libnss_files-2.23.so
b7118000-b7119000 r--p 0000a000 08:01 21496849   /lib/i386-linux-gnu/libnss_files-2.23.so
b7119000-b711a000 rw-p 0000b000 08:01 21496849   /lib/i386-linux-gnu/libnss_files-2.23.so
b711a000-b7120000 rw-p 00000000 00:00 0 
b7120000-b712b000 r-xp 00000000 08:01 21496770   /lib/i386-linux-gnu/libnss_nis-2.23.so
b712b000-b712c000 r--p 0000a000 08:01 21496770   /lib/i386-linux-gnu/libnss_nis-2.23.so
b712c000-b712d000 rw-p 0000b000 08:01 21496770   /lib/i386-linux-gnu/libnss_nis-2.23.so
b7151000-b7158000 r--s 00000000 08:01 48245384   /usr/lib/i386-linux-gnu/gconv/gconv-modules.cache
b7158000-b730b000 r--p 002d7000 08:01 48234512   /usr/lib/locale/locale-archive
b730b000-b750b000 r--p 00000000 08:01 48234512   /usr/lib/locale/locale-archive
b750b000-b750c000 rw-p 00000000 00:00 0 
b750c000-b76bb000 r-xp 00000000 08:01 21497064   /lib/i386-linux-gnu/libc-2.23.so
b76bb000-b76bc000 ---p 001af000 08:01 21497064   /lib/i386-linux-gnu/libc-2.23.so
b76bc000-b76be000 r--p 001af000 08:01 21497064   /lib/i386-linux-gnu/libc-2.23.so
b76be000-b76bf000 rw-p 001b1000 08:01 21497064   /lib/i386-linux-gnu/libc-2.23.so
b76bf000-b76c2000 rw-p 00000000 00:00 0 
b76c2000-b76c5000 r-xp 00000000 08:01 21497066   /lib/i386-linux-gnu/libdl-2.23.so
b76c5000-b76c6000 r--p 00002000 08:01 21497066   /lib/i386-linux-gnu/libdl-2.23.so
b76c6000-b76c7000 rw-p 00003000 08:01 21497066   /lib/i386-linux-gnu/libdl-2.23.so
b76c7000-b76e7000 r-xp 00000000 08:01 21496816   /lib/i386-linux-gnu/libtinfo.so.5.9
b76e7000-b76e9000 r--p 0001f000 08:01 21496816   /lib/i386-linux-gnu/libtinfo.so.5.9
b76e9000-b76ea000 rw-p 00021000 08:01 21496816   /lib/i386-linux-gnu/libtinfo.so.5.9
b76ef000-b7706000 r-xp 00000000 08:01 21496768   /lib/i386-linux-gnu/libnsl-2.23.so
b7706000-b7707000 r--p 00016000 08:01 21496768   /lib/i386-linux-gnu/libnsl-2.23.so
b7707000-b7708000 rw-p 00017000 08:01 21496768   /lib/i386-linux-gnu/libnsl-2.23.so
b7708000-b770a000 rw-p 00000000 00:00 0 
b770a000-b7712000 r-xp 00000000 08:01 21496134   /lib/i386-linux-gnu/libnss_compat-2.23.so
b7712000-b7713000 r--p 00007000 08:01 21496134   /lib/i386-linux-gnu/libnss_compat-2.23.so
b7713000-b7714000 rw-p 00008000 08:01 21496134   /lib/i386-linux-gnu/libnss_compat-2.23.so
b7714000-b7715000 r--p 002d4000 08:01 48234512   /usr/lib/locale/locale-archive
b7715000-b7717000 rw-p 00000000 00:00 0 
b7717000-b7719000 r--p 00000000 00:00 0          [vvar]
b7719000-b771a000 r-xp 00000000 00:00 0          [vdso]
b771a000-b773c000 r-xp 00000000 08:01 21497056   /lib/i386-linux-gnu/ld-2.23.so
b773c000-b773d000 rw-p 00000000 00:00 0 
b773d000-b773e000 r--p 00022000 08:01 21497056   /lib/i386-linux-gnu/ld-2.23.so
b773e000-b773f000 rw-p 00023000 08:01 21497056   /lib/i386-linux-gnu/ld-2.23.so
bff73000-bff94000 rw-p 00000000 00:00 0          [stack]

所示地址并不是真正的物理地址,而是虚拟地址.使用虚拟地址是出于对资源的保护 对系统来说,内存资源是宝贵的,而一个程序执行并不需要立即将所有资源加载到内存, 而实际上可采用写时申请的方法

虚拟地址的优点:

保护系统,避免用户程序非法访问内存造成内核崩溃.
节约资源,采用映射方法,使用时全用缺页的方法申请物理空间,即提高了效率也节约物理空间

3.进程地址空间的申请

32bit平台下,一个进程拥有4G的虚拟地址空间

映射规则
1. 代码段,数据段,BSS段,直接从磁盘拷贝至内存.在linux 32bit平台上起始地址一般为 0x08048000
2. 堆栈,动态变化.
3. mmap映射的文件(普通文件以及库),用户需自行调用mmap函数
4. 高地址1G空间:供内核映射处理,用户空间不能直接访问

堆和栈的起始地址是随机产生的,其目的是避免产生安全漏洞,但是可以使用brk/sbrk函数指定在堆中申请空间的起始地址

brk/sbrk函数声明

   #include <unistd.h>

   int brk(void *addr);  //指定下次申请堆空间的起始地址

   void *sbrk(intptr_t increment);  //在当前地址位置后移increament字节,为0时返回当前地址

代码示例:

 #include<stdlib.h>
 #include<stdio.h>
 int i = 10;
 int main(int argc,char *argv[])
 {
     brk(0x09e50000);
     printf("brk return:%p\n",sbrk(0));
     char *ptr = malloc(102400);
     printf("new malloc:%p \n",ptr);
     return 0;
 }

输出结果
brk return:0x9e50000
new malloc:0x9e51010

strace工具可以追踪进程空间的加载

4.空间分配规则

代码段,数据段,BSS段的地址在编译时已经固定.
BSS的结束段与堆的起始地址之间有一定间隙,间隙大小随机.
brk调整的仅仅是堆中申请空间的起始值
系统默认认为每个进程分配的堆空间大小是固定的.使用sbrk(0)得到的是我们堆空间的结束值.
真正编程中,很少使用brk/sbrk调整位置

5.栈的说明

栈:从高地址向低地址增长,起始值也是随机的.主要存放局部变量, 新调用子函数时函数的参数以及返回值,由OS自动管理.

Linux程序开发-命令行选项及参数

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Linux程序开发-命令行选项及参数

1.C语言中命令行参数的读取与输出

 #include <stdio.h>
 int main(int argc,char* argv[])
 {
    int i;
    for(i=0;i<argc;i++)
    {
        printf("argv[%d] = %s\n",i,argv[i]);
    }
 }

当命令行选项很多时,可以使用库函数获取

getopt      //短选项
getlongopt  //长选项

函数声明

 #include <unistd.h>
 int getopt(int argc,char* const argv[],const char *optstring);

以下全局变量用于配合getopt函数

extern char *optargr;
extern int optind;
extern int optopt;
extern int opterr;

2.有关选项和参数的区别

eg:

-a : 选项,一般表示所有

-h host: 其中,h表示选项,而host代表了一个主机ip也就是选项h的参数

具体参数的解析,可以参考getopt的第三个参数的使用约定

3.getopt的执行过程

当getopt每成功执行一次

extern char *optarg; //指向下一个要扫描的参数
extern int optind;   //索引修改为下一个要处理的指针的下标
extern int optopt;   //用于存储可能的错误
extern int opterr;   //如果opterr == 0;则不将错误输出到标准错误输出设备

4.getopt使用实例

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
int main(int argc,char** argv)
{
    int result;
    opterr = 0;
    while ((result = getopt(argc,argv,"ab:c::"))!= -1)
    {
        switch(result)
        {
        case 'a':
            printf("option=a,optopt=%c,optarg=%s\n",optopt,optarg);
            break;
        case 'b':
            printf("option=b,optopt=%c,optarg=%s\n",optopt,optarg);
            break;
        case 'c':
            printf("option=c,optopt=%c,optarg=%s\n",optopt,optarg);
            break;
        case '?':
            printf("result=?,optopt=%c,optarg=%s\n",optopt,optarg);
        default:
            printf("default,result=%c\n",result);
        }
        printf("argv[%d]=%s\n",optind,argv[optind]);
    }
    printf("result=-1,optind=%d\n",optind);
    return 0;
}

输入示例 ./first -a -b host -cShell

输出结果
option=a,optopt=,optarg=(null)
argv[2]=-b
option=b,optopt=,optarg=host
argv[4]=-cShell
option=c,optopt=,optarg=Shell
argv[5]=(null)
result=-1,optind=5

5.长选项判断函数getopt_long的声明

#include <unistd.h>

int getopt(int argc, char * const argv[],
                  const char *optstring);

extern char *optarg;
extern int optind, opterr, optopt;

#include <getopt.h>

int getopt_long(int argc,
                  char * const argv[],
                  const char *optstring,          //当前支持的短选项列表
                  const struct option *longopts,  //长选项信息
                  int *longindex);                //索引

struct option {
               const char *name;         //选项名
               int         has_arg;      //是否有参数
               int        *flag;         //标志
               int         val;          //返回值
                                };
int getopt_long_only(int argc, char * const argv[],
                  const char *optstring,
                  const struct option *longopts, int *longindex);

第四个参数的使用示例:

struct optino my_option = {
   {"help",0,NULL,'h'},
   {"output",1,NULL,'o'}
}

除了以上区别外,长选项与短选项的使用方法类似.

百度前端技术学院-任务7

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百度前端技术学院-任务七

任务七：实现常见的技术产品官网的页面架构及样式布局

style.css

* {
  padding: 0;
  margin: 0;
}

body {
  min-width: 1024px;
  font-family: 微软雅黑 ,sans-serif;
}

nav {
  height: 60px;
  width: 90%;
  margin: 0 auto;
}

a {
  text-decoration: none;
}

li {
  list-style: none;
}

.brand {
  float: left;
  height: 60px;
  line-height: 60px;
  font-size: 22px;
}

.brand em {
  display: inline-block;
  background: url(img/logo-middle.png) center center no-repeat;
  background-size:60%;
  width: 60px;
  height: 60px;
  float: left;
}

#nav-ul {
  float: right;
  height: 60px;
  line-height: 60px;
}


.nav-list {
  display: inline-block;
  width: 80px;
  text-align: center;
  height: 56px;
}

.fix {
  border-bottom: 4px solid red;
}

.nav-list a {
  text-decoration: none;
  color: #9E9E9E;
  font-size: 14px;
}

.nav-list:first-child a {
  color: red;
}

.nav-list:hover {
  border-bottom: 4px solid red;
}

.login {
  display: inline-block;
  background: url(img/login-icon.png) left center no-repeat;
  text-indent: 20px;
  color: red !important;
}

.poster {
  position: relative;
  background: url(img/back-img.jpg)no-repeat;
  background-size: 100%;
  height: 800px;
}

.slogan {
  position: absolute;
  left: 150px;
  top: 250px;
}

h2 {
  color: white;
  font-size: 70px;
  font-weight: normal;
  margin-bottom: 10px;
}

.slogan p {
  text-indent: 6px;
  color: white;
  font-size: 30px;
  margin-bottom: 5px;
}

.join-btn {
  margin-top: 40px;
  width: 300px;
  height: 50px;
  line-height: 50px;
}

.join-btn a {
  display: block;
  width: 100%;
  height: 100%;
  padding: 5px 0 5px 0;
  color: white;
  font-size: 25px;
  text-align: center;
  background-color: #e74f4d;
  letter-spacing: 3px;
  transition: background .3s;
}

.join-btn a:hover {
  background-color: #FF9800;
}

.effect {
  margin-top: 50px;
  overflow: hidden;
  margin-bottom: 50px;
}

.section-list {
  width: 25%;
  float: left;
  text-align: center;
}

.section-list p {
  padding-left: 55px;
  padding-right: 55px;
  color: #999;
  margin: 15px auto;
  letter-spacing: 1px;
  font-size: 15px;
  border-right: 2px solid #999;
}

.section-list:nth-child(4) p {
  border-right:0;
}

.introduce {
  text-align: center;
  background-color: #edecec;
  padding-top: 80px;
  padding-bottom: 80px;
}

.introduce h3 {
  padding-top: 30px;
  text-align: center;
  color: #a1a1a1;
  font-size: 50px;
  font-weight: normal;
  letter-spacing: 1px;
}

.map {
  height: 340px;
  background: url(img/map.jpg) no-repeat;
  background-size: 100%;
}

.map-introduce {
  padding-top: 50px;
  text-align: center;
  color: white;
}

.map-introduce p {
  font-size: 20px;
  padding-bottom: 3px;
}

.map-introduce span{
  margin: 0 auto;
  display: block;
  width: 20px;
  height: 2px;
  background-color:white;
  margin-bottom: 10px;
}

.map-introduce i{
  display: block;
  font-style: normal;
  font-size: 13px;
}

.select-con {
  width: 80%;
  margin: 0 auto;
  margin-top:50px;
}

.select-list {
  float: left;
  width: 20%;
  margin-right: 5%;
  position: relative;
  cursor: pointer;
}

.select-title {
  height: 35px;
  line-height: 35px;
  background-color: white;
  color: #000;
  text-indent: 10px;
  position: relative;
}

.email {
  display: block;
  position: absolute;
  top: 50%;
  right: 10px;
  width: 25px;
  height: 20px;
  margin-top: -10px;
  background-color: #be4e48;
}

.email em {
  position: absolute;
  top: 50%;
  left: 50%;
  margin-left: -4px;
  margin-top: -6px;
  z-index: 3;
  display: inline-block;
  width: 6px;
  height: 6px;
  border-left: 2px solid white;
    border-bottom: 2px solid white;
    transform:rotate(-45deg);
}

.select-list ul {
  display: none;
  width: 100%;
  position: absolute;
  top: 35px;
  left: 0;    
  background-color: #e4e3e5;
  padding-bottom: 15px;
  color: black;
}

.select-list:hover ul {
  display: block;
}

.select-list li {
  height: 30px;
  line-height: 30px;
  cursor: pointer;
}

.select-list li:hover {
  color: white;
  background-color: #be4e48;
}

.select-list li:hover i{
  opacity: 1;
}

.select-list i {
  opacity: 0;
  width: 20px;
  height: 20px;
  margin-right: 5px;
  margin-left: 5px;
  display: inline-block;
}

.select-list i:after{
  content: '√';
}

.select-btn {
  height: 35px;
  line-height: 35px;
  background-color: #be4e48;
  text-align: center;
  color: white;
  letter-spacing: 15px;
}

.activity {
  overflow: hidden;
  padding: 100px 0 100px 0;
  background-color: #f7f7f7;
}

.acvivity-con {
  width: 80%;
  text-align: center;
  margin: 0 auto;
}

.activity-list {
  width: 25%;
  float: left;
}

.activity-list img {
  border-width: 10px 7px;
  border-color: white;
  border-style: solid;
}

.act-site {
  padding-top: 15px;
  font-size: 15px;
}

.act-site-top {
  text-align: center;
  font-size: 20px;
  letter-spacing: 20px;
  text-indent: 20px;
}

.act-site-top + p{
  padding-bottom: 20px;
  color: #b5b5b5;
  font-size: 14px;
}

.activity-list p:nth-child(3) {
  color: #b5b5b5;
  padding-top: 5px;
  font-size: 14px;
}

.rule-1 {
  overflow: hidden;
}

.socks {
  text-align: center;
  color: white;
  position: relative;
  width: 66.7%;
  height: 44vw;
  min-height: 450px;
  background: url(img/socks.jpg) center center no-repeat;
  background-size: cover;
  float: left;
}

.socks-text {
  width: 400px;
  height: 300px;
  position: absolute;
  top: 50%;
  left: 50%;
  margin-left: -200px;
  margin-top: -150px;
}

.socks-text p:nth-child(1) {
  font-size: 3em;
}

.socks-text p:nth-child(2) {
  font-size: 8em;
  font-weight: lighter;
}

.socks-text p:nth-child(3),.socks-text p:nth-child(4) {
  font-size: 1.5em;
}

.trangle {
  width: 0;
    height: 0;
    border-top: 20px solid transparent;
    border-right: 40px solid white;
    border-bottom: 20px solid transparent;
    position: absolute;
    top: 50%;
    right: 0;
    margin-top: -20px;
}

.socks-right {
  position: relative;
  float: left;
  text-align: center;
  height: 44vw;
  min-height: 450px;
  width: 33.3%;
}

.world-content {
  position: absolute;
  height: 300px;
  width: 300px;
  top: 50%;
  left: 50%;
  margin-left: -150px;
  margin-top: -150px;
}

.world-content-title {
  font-size: 24px;
  height: 40px;
  line-height: 40px;
}

.world-content-title span:nth-child(2):after {
  content: '/';
  color: #666;

}

.world-content-title span:nth-child(3) {
  color: red;
}

.world-content p {
  margin-top: 20px;
  color: #aaaaaa;
  font-size: 14px;
  line-height: 30px;
}

.world-content a {
  display: block;
  width: 110px;
    height: 35px;
    line-height: 35px;
    margin: 40px auto 0 auto;
    text-align: center;
    border: 1px solid #e74f4d;
    color: #e74f4d;
    font-size: 13px;
    font-weight: bold;
}

.world-btn {
  text-align: center;
  margin-top: 10px;
}

.world-btn  span{
  display: inline-block;
    width: 10px;
    height: 10px;
    margin: 0 8px;
    border-radius: 5px;
    box-sizing: border-box;
    border: 1px solid #919292;
}

.selected {
  background-color: #919292;
}

.rule-2 {
  overflow: hidden;
}

.rule-part {
  float: left;
  width: 33.3%;
  min-height: 400px;
  height: 40vw;
  position: relative;
}

.new-time {
  text-align: center;
  width: 300px;
  height: 200px;
  position: absolute;
  top: 50%;
  left: 50%;
  margin-left: -150px;
  font-size: 1.3em;
  margin-top: -100px;
}

.new-time > * {
  margin-bottom: 20px;
}

.new-time span {
  display: inline-block;
  width: 30px;
  height: 2px;
  background-color: white;
}

.new-time a {
  display: block;
  color: white;
  width: 150px;
  height: 40px;
  line-height: 40px;
  margin: 0 auto;
  border: 2px solid white;
}

.red-bj {
  background-color: #e7504d;
  color: white;
}

.white-bj span {
  background-color: #abaaaa;
}

.white-bj a {
  border-color: #e7504d;
  color: #e7504d;
}

.photo-bj {
  background: url(img/woman.jpg) no-repeat;
  background-size: cover;
}

.left-trangle {
  width: 0;
    height: 0;
    border-top: 20px solid transparent;
    border-left: 40px solid white;
    border-bottom: 20px solid transparent;
    position: absolute;
    top: 50%;
    left: 0;
    margin-top: -20px;
}

.invitation {
  margin-top: 100px !important;
  overflow: hidden;

}

.invitation-title {
  margin-bottom: 50px !important;
  text-align: center;
}

.invitation-title h4 {
  font-weight: normal;
  font-size: 20px;
}

.invitation-title span {
  display: inline-block;
  width: 20px;
  height: 2px;
  background-color: #ea6563;
}

.invitation-title p {
  margin-top: 15px;
  color: #b7b7b7;
  font-size: 12px;
}

.invition-area {
  width: 80%;
  margin: 30px auto;
}

.invitation-protocol {
  float: left;
  width: 40%;
}

.invitation-login {
  width: 60%;
  float: left;
}

.invitation-protocol h4 {
  color: #807c7c;
  font-weight: normal;
  margin-bottom: 15px;
}

.invitation-protocol h4:nth-child(7) {
  margin-bottom: 0;
}

.invitation-protocol p {
  width: 80%;
  color:#6e6e6e;
  font-size: 12px;
}

.invitation-protocol span {
  display: inline-block;
  line-height: 15px;
  margin-right: 4px;
  width: 5px;
    height: 5px;
    border-left: 2px solid #ccc;
    border-bottom: 2px solid #ccc;
    transform: rotate(-45deg);
}

.invitation-protocol  a{
  width: 80%;
  height: 15px;
  line-height: 15px;
  display: block;
  text-align: right;
  color: #adabab;
  font-size: 10px;
  margin-bottom: 40px;
}

.input-group {
  padding-left: 3px;
    display: inline-block;
  width: calc(50% - 20px);
    margin: 5px;
    text-indent: 0px;
    background-color: #ededef;
    position: relative;
    cursor: pointer;
    font-size: 14px;  
}

.input-group:before {
  content: attr(data-label);
  position:absolute;
  height: 20px;
  line-height: 20px;
  top: 50%;
  margin-top: -12px;
}

.input-group input {
  text-indent: 80px;
  width: 100%;
  display: inline;
  background-color: #ededef;
  border: 0;
  height: 35px;
    line-height: 35px;
}

.textarea {
  width: calc(100% - 20px);
  font-size: 13px;
}

.textarea:before {
  height: 20px;
  line-height: 20px;
  top: 19px;
}

textarea {
  padding-top: 9px;
  width: 100%;
  height: 120px;
  background-color: #ededef;
  border:0;
  text-indent: 160px;
}

.login-row a {
  padding-left: 3px;
  text-align: center;
  width: calc(100% - 20px);
  height: 30px;
  line-height: 30px;
  display: block;
  margin: 5px;
  background-color: #ededef;
  color: black;
}

footer {
  margin-top: 100px;
}

.top-f {
  background-color: #32353e;
  height: 300px;
  position: relative;
}


.contact {
  width: 500px;
  height: 150px;
  position: absolute;
  top: 50%;
  left: 50%;
  margin-left: -250px;
  margin-top: -100px;
  text-align: center;
  color: white;  
}

.contact h4 {
  font-weight: lighter;
  font-size: 20px;
  padding-bottom: 8px;
}

.contact p {
  font-size: 14px;
}

.grid-email {
  position: relative;
  width: 80%;
  height: 45px;
  line-height: 45px;
  margin: 20px auto;
}

.grid-email:after {
  content: attr(data-label);
  background-color: #6f7278;
  position: absolute;
  top: 1px;
  right: 0;
  width: 70px;
  height: 45px;
  line-height: 45px;
  cursor: pointer;
}

.grid-email input {
  height: 45px;
  border: 0;
  width: 100%;
  text-indent: 15px;
  font-size: 18px;
}

.tools {
  text-align: center;
}

.tools a {
  display: inline-block;
  height: 30px;
  width: 30px;
  margin: 10px;
}

#qq {
  background: url(img/qq.png) center center no-repeat;
}

#weibo {
  background: url(img/weibo.png) center center no-repeat;
}

#twitter {
  background: url(img/twitter.png) center center no-repeat;
}

#earth {
  background: url(img/earth.png) center center no-repeat;
}

.bot-f {
  background-color: #2f2f38;
}

.links {
  width: 85%;
  height: 50px;
  margin: 0 auto;
}

.links a {
  color: white;  
  line-height: 50px;
  font-size: 12px;
}

.links a:nth-child(2) {
  float: right;
}

index.html

<!DOCTYPE html>
<html>
<head>
  <meta http-equiv="Content-Language" content="zh-ch"/>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <link rel="stylesheet" href="style.css" type="text/css"/>
  <title>任务七</title>
</head>
<body>
  <header>
      <nav>
          <div class="brand">
              <em></em>
              新世界
          </div>
          <ul id="nav-ul">
              <li class="nav-list fix"><a href="#">首页</a></li>
              <li class="nav-list"><a href="#">最新活动</a></li>
              <li class="nav-list"><a href="#">项目介绍</a></li>
              <li class="nav-list"><a href="#">爱心社区</a></li>
              <li class="nav-list"><a href="#" class="login">登录</a></li>
          </ul>
      </nav>
      <div class="poster">
          <div class="slogan">
              <h2 class="slogin-title">Time of new life</h2>
              <p>新时代，年轻的人们让我们一起</p>
              <p>体验新生活，享受新生活</p>

              <div class="join-btn">
                  <a href="#">开始体验</a>
              </div>
          </div>
      </div>
  </header>
  
  <div class="container">
      <section class="effect">
          <div class="section-list">
              <img src="img/icon-1.png" alt="">
              <p>打造全新世界，让你更爱你的生活</p>
          </div>
          <div class="section-list">
              <img src="img/icon-2.png" alt="">
              <p>丰富多彩的公益活动,发挥新世界的主人公意识</p>
          </div>
          <div class="section-list">
              <img src="img/icon-3.png" alt="">
              <p>时尚的新理念,超前体验未知的生活</p>
          </div>
          <div class="section-list">
              <img src="img/icon-4.png" alt="">
              <p>完善的培养机制,培养你的全新的世界观</p>
          </div>
      </section>

      <section class="introduce">
          <img src="img/logo-middle.png" alt="">
          <h3>关于新世界，你不知道的还有些什么</h3>   
      </section>

      <section class="map">
          <div class="map-introduce">
              <p>查找新世界城市活动信息</p>
              <span></span>
              <i>每个城市的有不同的信息,请自主查询您需要了解的城市</i>                
          </div>
          <div class="select-con">
              <div class="select-list">
                  <div class="select-title">中国
                      <em class="email"><em></em></em>
                  </div>
                  <ul>
                      <li><i></i>美国</li>
                      <li><i></i>法国</li>
                      <li><i></i>德国</li>
                      <li><i></i>新西兰</li>
                      <li><i></i>俄罗斯</li>
                      <li><i></i>日本</li>
                  </ul>
              </div>
              <div class="select-list">
                  <div class="select-title">省份
                      <em class="email"><em></em></em>
                  </div>
                  <ul>
                      <li><i></i>北京市</li>
                      <li><i></i>天津市</li>
                      <li><i></i>河北省</li>
                      <li><i></i>山西省</li>
                      <li><i></i>内蒙古自治区</li>
                      <li><i></i>辽宁省</li>
                  </ul>
              </div>
              <div class="select-list">
                  <div class="select-title">城市
                      <em class="email"><em></em></em>
                  </div>
                    <ul>
                        <li><i></i>广州</li>
                        <li><i></i>肇庆</li>
                        <li><i></i>增城</li>
                        <li><i></i>江门</li>
                    </ul>
              </div>
              <div class="select-list">
                  <div class="select-btn">搜索</div>
              </div>
          </div>
      </section>
      
      <section class="activity">
          <div class="acvivity-con">
              <div class="activity-list">
                  <img src="img/pic1.jpg" alt="">
                  <p class="act-site">北京活动</p>
                  <p>新社区大联盟</p>                       
              </div>
              <div class="activity-list">
                  <p class="act-site-top">上海活动</p>
                  <p>新社区大联盟</p>                       
                  <img src="img/pic2.jpg" alt="">
              </div>
              <div class="activity-list">
                  <img src="img/pic3.jpg" alt="">
                  <p class="act-site">深圳活动</p>
                  <p>全新海岸线观点站</p>                     
              </div>
              <div class="activity-list">
                  <img src="img/pic4.jpg" alt="">
                  <p class="act-site">香港活动</p>
                  <p>奢侈品消费大派送</p>                     
              </div>
              
          </div>
      </section>

      <section class="rules">
          <div class="rule-1">
              <div class="socks">
                  <div class="socks-text">
                      <p>新世界</p>
                      <p>TIME</p>
                      <p>@新世界-北京</p>
                      <p>2016.04.01</p>
                  </div>
                  <div class="trangle">    
                  </div>
              </div>
              <div class="socks-right">
                  <div class="world-content">
                      <div class="world-content-title">
                          <span>新世界</span>
                          <span></span>
                          <span>01</span>
                      </div>
                      <p>新世界新世界新世界新世界新世界新世界新世界新世界新世界新世界新世界新世界新世界新世界新世界新世界新世界新世界新世界新世界新世界新世界新世界新世界新世界新世界新世界</p>

                      <a href="#">点击详情</a>

                      <div class="world-btn">
                          <span class="selected"></span>
                          <span></span>
                          <span></span>
                      </div>
                  </div>
              </div>
          </div>

          <div class="rule-2">
              <div class="rule-part red-bj">
                  <div class="new-time">
                      <p>新时代</p>
                      <p>关于爱生活的我们</p>
                      <span></span>
                      <a href="#">查看更多</a>
                  </div>                    
              </div>    
              <div class="rule-part white-bj">
                  <div class="new-time">
                      <p>新时代</p>
                      <p>关于爱生活的我们</p>
                      <span></span>
                      <a href="#">查看更多</a>
                  </div>                    
                  
              </div>    
              <div class="rule-part photo-bj">
                  <div class="left-trangle">   
                  </div>
              </div>    
          </div>
      </section>

      <section class="invitation">
          <div class="invitation-title">
              <h4>成为我们的志愿者</h4>
              <span></span>
              <p>新世界的大家庭需要每一个爱生活的人的加入，如果你够年轻，有梦想，有激情<br>那就不要犹豫快来计入我们，改变所有人的生活</p>
          </div>
          <div class="invition-area">
              <div class="invitation-protocol">
                  
                      <h4>新世界志愿者协议</h4>
                      <p>加入新世界志愿者的人员必须遵守中华人民共共和国的
                          相关法律法规，并且本着平等资源的原则
                      </p>
                      <a href="#"><span></span>more</a>

                      <h4>新世界志愿者协议</h4>
                      <p>加入新世界志愿者的人员必须遵守中华人民共共和国的
                          相关法律法规，并且本着平等资源的原则
                      </p>
                      <a href="#"><span></span>more</a>

                      <h4>更多条款</h4>
                      <a href="#"><span></span>more</a>
              </div>

              <div class="invitation-login">
                  <div class="login-row">
                      <div class="input-group" data-label="姓名">   
                          <input type="text" name="name" id="name">                          
                      </div>
                      <div class="input-group" data-label="年龄">   
                          <input type="text" name="name" id="name">                          
                      </div>
                  </div>
                  <div class="login-row">
                      <div class="input-group" data-label="联系方式"> 
                          <input type="text" name="name" id="name">                          
                      </div>
                      <div class="input-group" data-label="联系地址"> 
                          <input type="text" name="name" id="name">                          
                      </div>
                  </div>
                  <div class="login-row">
                      <div class="input-group textarea" data-label="请简单描述您梦想的生活">   
                          <textarea></textarea>                       
                      </div>
                  </div>
                  <div class="login-row">
                      <a href="#">提交申请</a>   
                  </div>
              </div>
              
          </div>
      </section>
  </div>
  
  <footer>
      <div class="top-f">
          <div class="contact">
              <h4>联系我们</h4>
              <p>为了更好的获取我们最新的产品资讯，您可以留下您的电子邮箱快速订阅我们的产品资讯
              也可以通过以下任何方式关注我们动态</p>
              <div class="grid-email" data-label="提交">
                  <input type="email" placeholder="someone's@email.com">
              </div>
              <div class="tools">
                  <a href="#" id="qq"></a>
                  <a href="#" id="weibo"></a>
                  <a href="#" id="twitter"></a>
                  <a href="#" id="earth"></a>
              </div>
          </div>
      </div>
      <div class="bot-f">
          <div class="links">
              <a href="">@2016新世界</a>
              <a href="">back to top</a>
          </div>
      </div>
  </footer>
</body>
</html>

错误:Could Not Reserve Enough Space for Object Heap的解决方案

- -

错误:Could not reserve enough space for object heap的解决方案

Reason:

If you go thru this IBM link on java, it says that on 32 bit windows the recommended heap size is 1.5 GB and the Maximum heap size is 1.8 GB. So your jvm does not gets initialized for -Xmx2G and above.

Also if you go thru this SO answer, clearly the DLL bindings are an issue for memory reservation changing which is no trivial task. Hence what may be recommended is that you go for 64-bit Windows and a 64-bit JVM. while it will chew up more RAM, you will have much more contiguous virtual address space.

Method to fix:

For Windows

Go to Start → Control Panel → System → Advanced system settings → advanced(tab) → Environment Variables → System Variables → New:

Variable name: _JAVA_OPTIONS Variable value: -Xmx512M

For Linux

export _JAVA_OPTIONS=-Xmx512M

export _JAVA_OPTIONS=-Xmx1024M 

For Android Studio

Project > Gradle Scripts > gradle.properties

org.gradle.jvmargs=-Xms512m -Xmx1024m

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EdmondFrank's 时光足迹

この先は暗い夜道だけかもしれない　それでも信じて進むんだ。星がその道を少しでも照らしてくれるのを。
或许前路永夜，即便如此我也要前进，因为星光即使微弱也会我为照亮前途。
——《四月は君の嘘》

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