IPrintCoreUI2::EnumFeatures method (prcomoem.h)

Article
03/13/2023

The IPrintCoreUI2::EnumFeatures method enumerates a printer's available features.

Syntax

HRESULT EnumFeatures(
  [in]  POEMUIOBJ poemuiobj,
  [in]  DWORD     dwFlags,
  [out] PZZSTR    pmszFeatureList,
  [in]  DWORD     cbSize,
  [out] PDWORD    pcbNeeded
);

Parameters

[in] poemuiobj

Pointer to the current context, an OEMUIOBJ structure.

[in] dwFlags

Is reserved and must be set to zero.

[out] pmszFeatureList

Pointer to a caller-supplied buffer that receives a null-delimited list of feature keywords in MULTI_SZ format. The list is terminated with two null characters.

Set this parameter to NULL to simply query for the size (*pcbNeeded) of the feature list without having the list filled in.

[in] cbSize

Specifies the size, in bytes, of the buffer pointed to by pmszFeatureList.

[out] pcbNeeded

Pointer to a memory location that receives the actual size, in bytes, of the feature list.

Return value

This method must return one of the following values.

Return code	Description
S_OK	The method succeeded.
E_OUTOFMEMORY	The value in cbSize was smaller than the number of bytes to be written to the output buffer (the buffer pointed to by pmszFeatureList). The method was called with pmszFeatureList set to NULL.
E_INVALIDARG	The poemuiobj parameter pointed to an invalid context object.
E_FAIL	The method failed

Remarks

This method is supported only for Windows XP Pscript5 plug-ins, not for Unidrv plug-ins.

printer-sticky features (see Replacing Driver-Supplied Property Sheet Pages), such as those that determine installable memory and the presence of optional accessories, are included in the feature keyword list, which appears in the output buffer pointed to by pmszFeatureList when the method returns. For Pscript5, such features have the OpenGroupType feature attribute set to "InstallableOptions".

To reduce the need to make two calls per data access, pass the method an output buffer of a fixed size (1 KB, for example), and then check the function return value. If the method returns S_OK, the buffer already contains the data of interest. If the method returns E_OUTOFMEMORY, the value in *pcbNeeded is the buffer size needed to hold the data of interest. The caller should then allocate a buffer of that larger size and proceed with a second call to the method.

For more information, see Using EnumFeatures.

Requirements

Requirement	Value
Target Platform	Desktop
Header	prcomoem.h (include Prcomoem.h)