Opening a Queued Device Context

Before you can send data to a printer using device functions, you must open a device context with DevOpenDC. The parameters of DevOpenDC are influenced by the queue and job properties the user has chosen previously.

DevOpenDC accepts the following parameters as input:

hab

The anchor-block handle from a WinInitialize call.
lType
The type of device context. This always is OD_QUEUED to specify a queued device context.
pszToken
The device-information token. Always use an asterisk (*) for this parameter to force the system to get device information from the pdopData parameter.
lCount
The number of data elements supplied in the pdopData parameter. The minimum number of parameters for a queued device context is 4.
pdopData
The device-context data area. This is a pointer to a structure of the type DEVOPENSTRUC. The elements of this structure are described below.
hdcComp
The compatible-device-context handle. This must be NULL for a device context of type OD_QUEUED.

DevOpenDC returns a device-context handle of type HDC. The handle is used in other functions beginning with the Dev prefix and for GpiCreatePS and GpiAssociate.

The DEVOPENSTRUC structure contains all the data needed to define a device context.

The individual elements of the DEVOPENSTRUC structure are described below. At least the first four structure members must be provided for queued device contexts.

pszLogAddress

Name of the queue. It is the pszName field of the PRQINFO3 structure.

Note: For device contexts of type OD_INFO, pszLogAddress is the port name. This can be retrieved by calling SplQueryDevice using the pszPrinters device name. The pszLogAddr field in the PRQINFO3 structure is the port name.

pszDriverName
Character string identifying the printer driver, for example, LASERJET. The pszDriverName field of the PRQINFO3 structure, associated with the required print queue, gives the driver and device name, separated by a period, for example LASERJET.HP LaserJet IIID The pszDriverName field can contain only the name up to the period, for example LASERJET.
pdriv
This is a pointer to the job properties data returned by the printer driver from DevPostDeviceModes or the default job properties from pDriverData in the PRQINFO3 structure.

Note: The DRIVDATA structure contains the particular device name to be used. Therefore, it is a programming error to set this parameter to NULL.

pszDataType
It is recommended that PM_Q_STD always be used for the data type.
pszComment
Optional character string that the printer object displays to the user in a job settings notebook. It is recommended that the application include its own name in this comment string.

Note: The job title text is derived from the document name.

pszQueueProcName
Queue processor name (optional). The queue processor (also termed queue driver) name is available from the pszPrProc field of the PRQINFO3 structure. The default queue processor provided by the operating system is PMPRINT. The user also can install a queue processor (PMPLOT) that is used to provide reverse clipping for vector devices such as plotters.

For specialized applications, it is possible to use an alternative queue processor to the default specified for the queue. The list of installed queue processors is available from the OS2SYS.INI file using the application name PM_SPOOLER_QP.

pszQueueProcParams
Queue processor parameters (optional). They can include information such as the number of copies you want to print and the size of the output area on the printed page. See PMPRINT/PMPLOT Queue Processor Parameters for details.
pszSpoolerParams
Spooler parameters (optional) are separated by spaces. They are used for scheduling print jobs and are as follows:

• The form names that identify the paper to be used, for example, FORM=A4,A5,ENV. The form names are optional, but if they are provided, the spooler is able to hold off printing the jobs until the required form is installed in the printer. If the form name is not provided, the spooler attempts to print the job. The printer driver recognizes that there is a forms problem and displays a FORMS MISMATCH message box.

• Priority of the print job, for example, PRTY=60. The priority is specified as an integer in the range 1 through 99; 99 is the highest. The default priority value is 50. The application can use the spooler priority parameter to prioritize its own jobs. However, it is not good practice for an application always to use priority 99 in an attempt to get its jobs printed first.
pszNetworkParams
Optional parameter that can be used to specify network options; for example, USER=JOESMITH.

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