IBM AIX Continuous Availability Features - IBM Redbooks

Example 3-41 Sample Vue script pvue2.e
#!/usr/bin/probevue
/*
* Strings are by default Global variables
*/
String global_var[4096];
/*
* Global variables are accessible throughout the scope of Vue file in any clause
*/
__global global_var1;
__kernel long lbolt;
/*
* Thread variables are like globals but instantiated per traced thread first
* time it executes an action block that uses the variable
*/
__thread int thread_var;
/*
* Built-in variables are not supposed to be defined. They are by default
* available to the clauses where is makes any sense. They are : __rv, __arg1,
* __pid etc. __rv (return value for system calls) makes sense only when system
* call is returning and hence available only for syscall()->exit() action block.
* While __arg1, __arg2 and arg3 are accessible at syscall()->entry(). As system
* call read() accespts only 3 arguments so only __arg1, __arg2 and __arg2 are
* valid for read()->entry() action block.
* __pid can be accessed in any clause as current process id is valid everywhere
*/
int read(int fd, void *buf, int n);
@@BEGIN
{
global_var1=0;
lst=list();
printf("lbolt=%lld\n",lbolt);
}
@@uft:$1:*:printf:entry
{
global_var1=global_var1+1;
append(lst,1);
}
/*
* Valid built-in variables : __pid, __arg1, __arg2, __arg3
* __rv not valid here, its valid only inside read()->exit()
*/
@@syscall:*:read:entry
when ( __pid == $1 )
{
/*
* Automatic variable is not accessible outside their own clause. So auto_var
Chapter 3. AIX advanced continuous availability tools and features 123