Trace - Control Data Corporation 3300 Reference Manual

4.7.27
TRACE
4-70
The TRACE statement is a source language debugging tool which enables the
user to display literals and the contents of data names on the job standard
output file during execution of the object program.
TRACE [WHEN integer-I] [EVERY integer-2] [UNTIL integer-3]
{
literal-l } [{literal-2 }]
data-name-l 'data-name-2 ....
Any number of TRACE statements may be inserted in the Procedure
Division of a COBOL source program.
Compilation of TRACE statements is controlled by the TRACE parameter on
the UCBL control card for the program. When the T parameter is specified,
all TRACE statements are compiled into the object program at the points of
occurrence.
During program execution, as each compiled TRACE request is encountered,
each specified literal value is displayed as given. The contents of data names
are displayed in edited form according to the edit picture assigned to each
data name. The data name followed by a space, an equal sign and another
space are presented preceding the value. All literals and values are displayed
in a linear fashion across the print line.
WHEN integer-l indicates the first execution of the TRACE statement. Each
time the program enters a TRACE request, a counter initially set to one is
incremented by one and a comparison is made with the value given as integer-I.
When the counter equals integer-I, the literals and values for the request are
displayed for that cycle and all successive integer-2 cycles, until integer-3
has been reached.
If
WHEN integer-l is omitted, the TRACE begins at the
first cycle.
EVERY integer-2 indicates the timing between each display.
If
this option is
omitted, a display is generated during each cycle of the TRACE request.
UNTIL integer-3 indicates the maximum number of TRACE cycles to be
processed before the request becomes inoperative. If the option is omitted,
the TRACE request is processed until program execution is ended.
A TRACE statement may be continued on succeeding source lines, it may
begin on or after column 12.
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