close函数,用来关闭已打开的文件.
 
(1).语法
 
       int close(int fd)
 
      说明:该函数用来关闭已打开的文件.指定的参数fd为open()或creat()打开的文件
 
                 描述符.
 
      返回值:关闭成功返回0,失败则返回-1.
 
      详解:close()函数用来关闭一个已打开的文件,并且将文件修改过的内容写回磁盘
 
                任何有关该文件描述符上的记录锁,和使用该文件的进程都会被关闭和移除
 
       实例:
 
                 #include<stdio.h>
                 #include<stdlib.h>
                 #include<fcntl.h>
                 #include<unistd.h>
 
                  int main(void)
                  {
                               int fd;
                               fd=open("test.txt",O_RDWR|O_CREAT,00777);
                               if(fd<0)
                               {
                                       printf("Faile to open file\n");
                                        exit(1);
                                }
                                else
                                {
                                         printf("Success to open file\nFile Description is %d\n",fd);
                                         if(close(fd)==0)
                                         {
                                                  printf("Success to close file\n");
                                          }
                                          else
                                           {
                                                   printf("Faile to close file\n");
                                            }
                                   }
                                  return 0;
                      }