SUMMARY

Controls the tracing of blackboard and header variables.

SYNTAX

TRACE [ON|OFF] name [name ...]

INPUT

ON:	Turn tracing on for variables that follow.
OFF:	Turn tracing off for variables that follow.
name:	The name of the blackboard or header variable to trace. If this is a header variable it is of the form: filename,hdrname where filename is the name (or number) of the SAC data file and hdrname is the name of a SAC header variable.

DEFAULT VALUES

TRACE ON

DESCRIPTION

This command can be used to trace or track the values of SAC blackboard or header variables while SAC is executing. It is useful primarily for debugging long or complicated macros. When the tracing for a variable is turned on, its current value is printed. While the tracing is on, its value is checked after the execution of each command. Each time its value changes a new output line is printed. When tracing is turned off, its current value is also printed.

EXAMPLES

To turn tracing on for the blackboard variable called TEMP1 and for the header variable called T0 belonging to the file called MYFILE:

SAC> TRACE ON TEMP1 MYFILE,T0
    TRACE  (on) TEMP1 = 1.45623
    TRACE  (on) MYFILE,T0 = UNDEFINED

As you execute commands, either typed at the terminal or executed from a macro, SAC will check the values of the variables versus the saved value and print a message whenever either one of them changes. Assume that some calculations are performed that caused TEMP1 to change and T0 to become defined. SAC would print the messages:

TRACE (mod) TEMP1 = 2.34293
TRACE (mod) MYFILE,T0 = 10.3451

Later in the processing TEMP1 may change again:

TRACE (mod) TEMP1 = 1.93242

When the tracing is turned off, SAC will print the current value one last time:

SAC> TRACE OFF TEMP1 MYFILE,T0
    TRACE (off) TEMP1 = 1.93242
    TRACE (off) MYFILE,T0 = 10.3451

LATEST REVISION

January 27, 1989 (Version 10.4B)