The following table provides a brief summary of deviceparameters for null devices. For more detailed information, refer to the sections following the OPEN, USE, and CLOSE commands.
|
Null Deviceparameters |
||
|
DEVICEPARAMETER |
COMMAND |
COMMENT |
|
EXCEPTION=expr |
O/U/C |
Controls device-specified error handling. For the null device this is only EOF handling and therefore exceptions can never be invoked except by a READ. |
|
[NO]FILTER[=expr] |
U |
Controls some $X,$Y maintenance. |
|
LENGTH=intexpr |
U |
Controls the length of the virtual page. |
|
WIDTH=intexpr |
U |
Controls maximum size of a record. |
|
[NO]WRAP |
O/U |
Controls handling of records longer than the maximum width. |
|
X=intexpr |
U |
Sets $X to intexpr. |
|
Y=intexpr |
U |
Sets $Y to intexpr. |
O: Applies to the OPEN command
U: Applies to the USE command
C: Applies to the CLOSE command