【LoadRunner技术讲座8】LoadRunner函数中的几个陷阱

无意中看到此文,写的不错,分享,原文如下:

1、atof

  在LoadRunner中如果直接用:

 

  float f;

  f=atof("123.00");

  lr_output_message("%f",f);

 

  输出的结果会是1244128.00,根本不是我们想要的。

  因为float,double型在不同的平台下长度不一样,所以在loadrunner中调用atof需要显式的声明这个函数

  如下:

 

  doubleatof (const char *string);

  float f;

  f=atof("123.00");

  lr_output_message("%.2f",f);

 

  这样就能输出结果:123.00。

  其实,在LR关于atof的帮助文档描述中有提到这点,要求使用这个函数前“must be explicitly declared in Vugen scripts. ”,同样的要求也出现在atol函数的描述中。

  2、lr.save_string

  在LoadRunner中,使用.NET VUser时可以使用lr.save_string来存入一个变量,但是其使用方法却与通常使用的lr_save_string有区别,不小心的话容易“中招”。

  C语言的lr_save_string的定义如下:

 

  int lr_save_string (const char *param_value, const char *param_name);

 

  注意:参数值在前面,参数名在后面。

  而.NET VUser的lr.save_string的参数使用恰好相反,参数名在前面,参数值应该放到后面。

  但是LR的帮助文档并没有关于lr.save_string的定义,如果在脚本中选中“lr.save_string”,然后按F1,则直接蹦到lr_save_string的定义描述中,极容易误导人!

3、ftp_put

  ftp_put 是LoadRunner中的FTP函数,用于上传文件到FTP服务器。定义如下:

 

  int ftp_put ( char *transaction, LAST);

 

  查看LR的帮助文档可获得如下例子:

 

  // Send the file "ftp_file.txt" to the for_jon directory.

  ftp_put("Ftp_Put",

  "PATH=f:/ftp_file.txt", "TARGET_PATH=/pub/for_jon", "MODE=ASCII",

  ENDITEM ,

  LAST);

 

  当你兴匆匆地以为拿过来修改一下就可以用了的时候,LR却提示如下错误:

  Starting action Action.

  globals.h(101): Warning message:PATH=D:/ftp.txt is not ftp_put valid option

  globals.h(101): Debug message:Putting file test.txt in /Qdownload/test.txt, passive mode set to 0

  globals.h(101): Error -86026:Failed to open D:\LoadRunner\LRProject\lr_FTP1\test.txt for reading.

  globals.h(101): Error -86027:Failed to put data: 226 Transfer complete

  Abort was called from an action.

  提示错误是文件不能读,但是文件明明就不在错误所提示的D:\LoadRunner\LRProject\lr_FTP1\test.txt 中,而是在D:/ftp.txt。

  后来看到错误提示之前的一个Warning写道PATH=D:/ftp.txt is not ftp_put valid option,难道错误是这里引起的?查看帮助文档关于item_list的描述可知:

  item_list

  A list of all the items for this function. Enclose all entries with quotes.

  SOURCE_PATH: The file to upload to the FTP server.

  OR

  MSOURCE_PATH - Like SOURCE_PATH, but using wildcards to specify multiple files. If wildcards are not specified, all the files in the MSOURCE_PATH are uploaded.

  TARGET_PATH (optional) - the path and filename in which to place the file.

  if (M)SOURCE_PATH is specified, but TARGET_PATH is not specified, the file is stored in the root directory of the FTP server, with the original file name.

  MODE (optional) - Retrieval mode ASCII or BINARY (default).

  PASSIVE (optional) - Sets the communication protocol to Passive Mode FTP. To enable, pass "PASSIVE=TRUE".

  ENDITEM - Marks the end of the list. (no quotes)

  原来是SOURCE_PATH而不是例子所说的PATH,好吧,等你改成SOURCE_PATH后,如下所示:

 

  // Send the file "ftp_file.txt" to the for_jon directory.

  ftp_put("Ftp_Put",

  "SOURCE_PATH=f:/ftp_file.txt", "TARGET_PATH=/pub/for_jon", "MODE=ASCII",

  ENDITEM ,

  LAST);

 

  兴匆匆地以为就行了,一运行又报错:

  globals.h(101): Error -86025:Put failed; 550 /pub/for_jon: Not a regular file

  原来这次是TARGET_PATH的问题,再看LR的帮助文档:

  TARGET_PATH (optional) - the path and filename in which to place the file.

  if (M)SOURCE_PATH is specified, but TARGET_PATH is not specified, the file is stored in the root directory of the FTP server, with the original file name.

  原来TARGET_PATH要包含文件名,因此改成:

 

  // Send the file "ftp_file.txt" to the for_jon directory.

  ftp_put("Ftp_Put",

  "SOURCE_PATH=f:/ftp_file.txt", "TARGET_PATH=/pub/for_jon/ftp_file.txt", "MODE=ASCII",

  ENDITEM ,

  LAST);

 

  这次终于行了。

  同样的,在ftp_put_ex函数中也有类似的错误:

 

  In the following example, the ftp_get_ex function gets the file ftp_file.txt from the FTP server.

  // Send the file "ftp_file.txt" to the for_jon directory.

  ftp_put_ex(&ftp, "Ftp_Put",

  "PATH=f:/ftp_file.txt", "TARGET_PATH=/pub/for_jon", "MODE=ASCII",

  ENDITEM,

  LAST);

 

  而且例子代码写的是“ftp_put_ex”, 描述例子时却说的是“ftp_get_ex”。

  LR是非常优秀的性能测试工具,但是如果帮助文档中类似这样的错误比较多的话,对初学者而言就又多了一道学习的门槛:鉴别联机帮助信息的真伪的能力。 

 

你可能感兴趣的:(函数,职场,休闲)