System; Warn; Context At The Probe Point; Backtrace - Red Hat ENTERPRISE LINUX 5.4 - SYSTEMTAP LANGUAGE Reference Manual

Chapter 9. Predefined functions
This function operates like printf, but returns the formatted string rather than printing it.

9.1.10. system

General syntax:
system (cmd:string)
The system function runs a command on the system. The specified command runs in the background
once the current probe completes.

9.1.11. warn

General syntax:
warn:unknown (msg:string)
This function sends a warning message immediately to staprun. It is also sent over the bulk transport
(relayfs) if it is being used. If the last character is not a newline, then one is added.

9.2. Context at the probe point

The following functions provide ways to access the current task context at a probe point. Note that
these may not return correct values when a probe is hit in interrupt context.

9.2.1. backtrace

General syntax:
backtrace:string ()
Returns a string of hex addresses that are a backtrace of the stack. The output is truncated to
MAXSTRINGLEN.

9.2.2. caller

General syntax:
caller:string()
Returns the address and name of the calling function. It works only for return probes.

9.2.3. caller_addr

General syntax:
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