有时，我们需要使用DTrace追踪程序的链接库的函数，这时module名字就应该是链接库的名字。什么样的名字是有效的呢？让我做个实验验证一下。

我的程序链接了MySQL的client库，执行下面这些命令：

bash-3.2# dtrace -n 'pid$target::mysql_real_connect:entry' -p 10848
dtrace: description 'pid$target::mysql_real_connect:entry' matched 1 probe
^C

bash-3.2# dtrace -n 'pid$target:mysqlclient_r:mysql_real_connect:entry' -p 10848
dtrace: invalid probe specifier pid$target:mysqlclient_r:mysql_real_connect:entry: probe description pid10848:mysqlclient_r:mysql_real_connect:entry does not match any probes

bash-3.2# dtrace -n 'pid$target:libmysqlclient_r:mysql_real_connect:entry' -p 10848
dtrace: description 'pid$target:libmysqlclient_r:mysql_real_connect:entry' matched 1 probe
^C

bash-3.2# dtrace -n 'pid$target:libmysqlclient_r.so:mysql_real_connect:entry' -p 10848
dtrace: description 'pid$target:libmysqlclient_r.so:mysql_real_connect:entry' matched 1 probe
^C

bash-3.2# dtrace -n 'pid$target:libmysqlclient_r.so.15:mysql_real_connect:entry' -p 10848
dtrace: description 'pid$target:libmysqlclient_r.so.15:mysql_real_connect:entry' matched 1 probe
^C

bash-3.2# dtrace -n 'pid$target:libmysqlclient_r.so.15.0:mysql_real_connect:entry' -p 10848
dtrace: description 'pid$target:libmysqlclient_r.so.15.0:mysql_real_connect:entry' matched 1 probe
^C

bash-3.2# dtrace -n 'pid$target:libmysqlclient_r.so.15.0.0:mysql_real_connect:entry' -p 10848
dtrace: description 'pid$target:libmysqlclient_r.so.15.0.0:mysql_real_connect:entry' matched 1 probe
^C

可以看到，libmysqlclient_r，libmysqlclient_r.so，libmysqlclient_r.so.15，libmysqlclient_r.so.15.0和libmysqlclient_r.so.15.0.0都是有效的module名称，但是mysqlclient_r不行。此外省略module名也可以。