| |
|
| Formats |
Where:
| stmtref |
Program
line number or statement label to which to
transfer control. |
| varlist |
Comma-separated
list of variable names to be tested as a string. |
| prglvl |
Program
execution level whose program's 'changed' state
is going to be returned. Negative values indicate
value relative current program level. |
|
| |
|
| Returns |
String,
listing variables that have changed. (format 1 & 2)
Numeric, 0 or 1 Indication program has changes (format 3) |
| |
|
| Description |
Use
the CHG( ) function to determine whether
or not the value of a variable has changed. Given a comma-separated
list of variable names, the CHG( )
function will return a comma-separated
list of those variables that have changed. Use += (add
to), -=
(subtract from), and other operators with the CHG(
) function. |
|
|
| *Note* |
You
should not use the CHG( ) function with
NOMADS applications (except for variables not referenced
by the panel), because when you set the REFRESH_FLG,
NOMADS itself uses the CHG( ) function
to determine which variables are to be refreshed. |
|
|
| |
|
| Format
1 |
Notify
& Change Status
CHG(varlist[,ERR=stmtref])
The "changed"
status of a variable is changed when the data in the
variable changes or when the CHG( ) function
is applied. This format of the CHG( )
function will reset the "changed" status of the
variables listed; e.g.,
0010 PRINT
CHG("A,B,D$,E$")
0020 LET A=1.234
0030 LET
E$="MIKEY"
0040 PRINT
CHG("A,B,D$,E$") ! Prints A,E$
0050 PRINT
CHG("A,B,D$,E$") ! Prints nothing
|
| |
|
| Format
2 |
Non-Destructive Read
CHG(READ
varlist[,ERR=stmtref])
The CHG(READ ) format
allows you to do a non-destructive read
of the value returned by the CHG( ) function.
The "changed" status will not be reset when the
function is applied; e.g.,
0010 PRINT
CHG("A,B,D$,E$")
0020 LET A=1.234
0030 LET
E$="MIKEY"
0040 PRINT CHG(READ
"A,B,D$,E$") ! Prints A,E$
0050 PRINT
CHG("A,B,D$,E$") ! Prints A,E$
|
| |
|
| Format 3 |
Get
program changed state
CHG (
prglvl [,ERR=stmtref])
This format of the CHG
function allows you to determine if the program running
at the level specified has been changed. The function
will return 0 if the program has not been changed, 1 if
it has.
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