LoadRunner如何在脚本运行时修改log设置选项？

LoadRunner如何在脚本运行时修改log设置选项？答案是使用lr_set_debug_message函数：
 

lr_set_debug_message
Sets the message level for the script execution.
 
int lr_set_debug_message (unsigned int message_level, unsigned int on_off);
 
例子：
lr_set_debug_message(LR_MSG_CLASS_EXTENDED_LOG |             LR_MSG_CLASS_FULL_TRACE, LR_SWITCH_ON );

rc = lrd_fetch(Csr1, 1, 1, 0, PrintRow3);

if (rc>2000)
    lr_debug_message(LR_MSG_CLASS_FULL_TRACE,
             "Fetch failed returned %d", rc);

/* Now reset message class to former level */
lr_set_debug_message(LR_MSG_CLASS_EXTENDED_LOG |             LR_MSG_CLASS_FULL_TRACE, LR_SWITCH_OFF );
 
 
参数message_level的设置与LR的run-time设置界面中的选项有对应关系，可参考下表以及LR的帮助文档：
Each logging option has a C-constant that is a binary value with a 1 in the position that corresponds to the log option.

Log Level	C Constant	Value	Binary Value
Disabled	LR_MSG_CLASS_DISABLE_LOG	0	00000000 00000000
Brief	LR_MSG_CLASS_BRIEF_LOG	1	00000000 00000001
Extended Log	LR_MSG_CLASS_EXTENDED_LOG	16	00000000 00010000
Result Data	LR_MSG_CLASS_RESULT_DATA	2	00000000 00000010
Parameter Substitution	LR_MSG_CLASS_PARAMETERS	4	00000000 00000100
Full Run-Time Trace	LR_MSG_CLASS_FULL_TRACE	8	00000000 00001000
Log on Error	LR_MSG_CLASS_JIT_LOG_ON_ERROR	512	00000010 00000000

 
 
在脚本动态设置log选项前，可以采用下面的函数来清空已有的设置：

// Turn off all logging options (this is the same as having logging disabled).

void jds_clear_log_options(void) {

      unsigned int log_options = lr_get_debug_message();

      lr_set_debug_message(log_options, LR_SWITCH_OFF);

      return;

}

 
脚本中使用了lr_get_debug_message函数来取得当前的设置。
 
 
参考：
http://www.jds.net.au/tech-tips/loadrunner-log-options/