LR文件输入输出函数

Input Output functions allow you to read and write to files. Most of these functions begin with anfprefix. Expand the category to view a list of the available functions.

例子：The following example opens a log file and writes the string to it using fputc.

   //预处理命令之条件编译,如果已经定义了#define，取#ifdef,现取#else部分

   #ifdef unix

       char * filename = "/tmp/logfile.txt";

   #else

       char * filename = "D:\\logfile.txt"; //运行前现在路径下建立文件

   #endif

   long file; //使用long来取代文件指针File *fp来声明变量

   char * p, str[] = "this is the first line of the log file";

   int c;

   //创建新文件

   //通过判断file的值与NULL是不是相等来验证文件是否正常打开

   if ((file=fopen(filename,"w+"))==NULL) {

       lr_output_message("Unable to create %s",filename);

       return -1;

   }

   //向文件中写入字符串

   p = str; //p指针指向数组str的第一个字符

   //文本文件结束标记EOF，十进制为-1，十六进制为oxff，while后跟一空语句

   while ((*p != NULL) && fputc(*(p++), file) != -1);

   fclose(file);

  例子：The following example, for Windows platforms, opens a file and reads 3 characters into a buffer using fgetc.

  #define NUM_CHARS 3

  int i,total=0;

  char buffer[100],ch;

  long file;

  char *filename="D:\\readme.txt";

  //只读方式打开文件，并且file指向文件，如果为NULL，文件为正常打开

  if((file=fopen(filename,"r"))==NULL) {

      lr_error_message ("Cannot open %s", filename);

       return -1;

  }

  //feof未读取到文件末尾返回0，否则返回非零值

  for (i=0; (i<NUM_CHARS) && (feof(file) == 0); i++) {

     ch=fgetc(file);

     buffer[i]=ch;

  }

  buffer[i]=NULL;

  lr_output_message("First %d characters of file %s are \"%s\"",NUM_CHARS,filename,buffer);

  if (fclose(file))//文件关闭成功返回0，否则返回EOF

  lr_error_message ("Error closing file %s", filename);

  例子：The following example, for Windows platforms, opens a file and reads the first line using fgets.

   int i,total=0;

   char line[100],ch;

   long file;

   char *filename ="D:\\readme.txt";

   ////通过判断  file的值与NULL是不是相等来验证文件是否正常打开

   if((file=fopen(filename,"r"))==NULL) {

       lr_error_message("Cannot open %s",filename);

       return -1;

   }

   //获得文件中第一行字符串

   if((fgets(line,100,file)==NULL))

     lr_output_message("fgets error");

   else

       lr_output_message("The first line is \"%s\"",line);

   if(fclose(file))

       lr_error_message("Error closing file %s",filename);

  例子：The following example opens a log file and writes the id number and group name of the Virtual User to it using fprintf.

  //预处理命令之条件编译,如果已经定义了#define，取#ifdef,现取#else部分

   #ifdef unix

       char * filename = "/tmp/logfile.txt";

   #else

       char * filename = "D:\\logfile.txt";

   #endif

   long file;

   int id;

   char * groupname;

   //<span style='fon

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