Caché ObjectScript Reference - InterSystems Documentation

Caché ObjectScript Commands• Device alias, specified as a positive integer. A device alias refers to a physical devicenumber.• File pathname, specified as a quoted string. This is used for opening sequential files. Apathname can be canonical (c:\myfiles\testfile) or relative to the current directory(\myfiles\testfile).See "Specifying the Device" for more information.parametersThe list of parameters used to set operating characteristics of the device to be opened. Theenclosing parentheses are required if there is more than one parameter. (It's good programmingpractice to always use parentheses when you specify a parameter.) Note the required colonbefore the left parenthesis. Within the parentheses, colons are used to separate multipleparameters.The parameters for a device can be specified using either positional parameters or keywordparameters. You can also mix positional parameters and keyword parameters within the sameparameter list.In most cases, specifying contradictory, duplicate, or invalid parameter values does not resultin an error. Wherever possible, Caché ignores inappropriate parameter values and takesappropriate defaults.If you do not specify a list of parameters, Caché uses the device's default parameters. Thedefault parameters for a device are configurable. Go to the System Management Portal, selectSystem Configuration, select Advanced Settings, on the pull-down Category list select Devices.Click “contents” to display the current list of devices. For the desired device, click “edit”to display its Open Parameter: option. Specify this value in the same way you specify theOPEN command parameters, including the enclosing parentheses. For example,("AVL":0:2048).The available parameters are specific to the type of device that is being opened. For moreinformation on device parameters, see I/O Devices and Commands in Caché I/O DeviceGuide.Positional ParametersPositional parameters must be specified in a fixed sequence in the parameter list. You canomit a positional parameter (and receive the default value), but you must retain the colon toindicate the position of the omitted positional parameter. Trailing colons are not required;excess colons are ignored. The individual parameters and their positions are highly devicedependent.There are two types of positional parameters: values and letter code strings.102 Caché ObjectScript Reference