XDCscript - Capsule-Object.$trace

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[printable version]  [offline version]offline version generated on 17-Jul-2018 11:07 UTC

XDCscript - Capsule-Object.$trace

Print a trace message



this.$trace(msg [, level, [groups]]);


message string to output if trace for the current capsule is enabled.
this optional integer value specifies the trace "level" of this statement; msg will only be output if the trace level requested is greater than or equal to the level.
this optional array of strings identifies the trace groups to which this statement belongs; msg will only be displayed if one or more of the specified trace group names listed in the groups array have been enabled.


The string msg is output if trace is enabled for this capsule. The only required argument is msg. Default value for level is 0, and if groups is left unspecified, the trace statement will belong only to the group all, which contains all trace statements. Level 0 is the least verbose, while larger values generally provide more information.

Trace is enabled via xdc.traceEnable().


Suppose the package pkgA contains the file package.xs with the following content:

function init()
    $trace("init ...");
function close()
    $trace("closing ...", 0, ["pkgClose"]);
function validate()
    $trace("validating ...", 1, ["pkgValidate"]);

The configuration script

var Trace = xdc.module("xdc.services.global.Trace");

or the command line


generates the following trace output:

TIME=10:36:46.730 AM -- C:/rep/pkgA/package.xs: init ... (pkgInit, all)
TIME=10:36:46.860 AM -- C:/rep/pkgA/package.xs: closing ... (pkgClose, all)

Notice that the output does not show output from the validate() function. This is because the trace level passed to $trace() is 1 and the default trace level is 0. In this example, to see output from all $trace statements you must also set the trace level to 1 (or more). For example, the command line:


generates the following trace output:

TIME=10:43:36.804 AM -- C:/rep/pkgA/package.xs: init ... (pkgInit, all)
TIME=10:43:36.934 AM -- C:/rep/pkgA/package.xs: closing ... (pkgClose, all)
TIME=10:43:37.555 AM -- C:/rep/pkgA/package.xs: validating ... (pkgValidate, all)

See also

XDCscript - Capsule-Object.$traceQuery Query whether capsule trace is enabled
XDCscript - xdc.traceEnable Enable debug trace output
Trace Support Tracing the execution of XDCscript

[printable version]  [offline version]offline version generated on 17-Jul-2018 11:07 UTC
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