Print debugging statement: Difference between revisions

=={{header|COBOL}}==

Works with GnuCOBOL.

Explicit debug usually just uses DISPLAY, and usually directed at SYSERR. Compiler Directing Facility debug is supported with <code>>>D</code> directive statements. GnuCOBOL also supports full on line step tracing, controlled by both compile time switch, <code>-ftraceall</code>, and a truthy setting in a `COB_SET_TRACE` environment variable (so program step logging can be switched on and off without a recompile (for tracking down pesky production run mysteries)).

<lang cobol>gcobol*>

*> steptrace.cob

*> Tectonics: cobc -xj -fdebugging-line -ftraceall steptrace.cob

*> export COB_SET_TRACE=Y

*>

identification division.

program-id. steptrace.

data division.

working-storage section.

procedure division.

steptrace-main.

display "explicit line" upon syserr

>>Ddisplay "debug line" upon syserr

goback.

end program steptrace.</lang>

That is fixed form COBOL, columns 1 through 6 ignored by the preprocessor (historical format, from the days of punch card input) with column 7 being a special indicator column, star for comments, dash for continuations, and D is supported by GnuCOBOL for Debug lines. The <code>>>D</code> form is a newer addition to the Compiler Directing Facility, and can float anywhere on a free format compile line.

{{out}}

<pre>prompt$ cobc -xj -fdebugging-line -ftraceall steptrace.cob

explicit line

debug line

prompt$ cobc -xj -ftraceall steptrace.cob

explicit line

prompt$ export COB_SET_TRACE=Y

prompt$ ./steptrace

Source: 'steptrace.cob'

Program-Id: steptrace Entry: steptrace Line: 22

Program-Id: steptrace Section: (None) Line: 22

Program-Id: steptrace Paragraph: steptrace-main Line: 22

Program-Id: steptrace Statement: DISPLAY Line: 24

explicit line

Program-Id: steptrace Statement: GOBACK Line: 28

Program-Id: steptrace Exit: steptrace</pre>