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VARSTRING structure (tapi.h)

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The VARSTRING structure is used for returning variably sized strings. It is used both by the line device class and the phone device class.

Syntax

typedef struct varstring_tag {
  DWORD dwTotalSize;
  DWORD dwNeededSize;
  DWORD dwUsedSize;
  DWORD dwStringFormat;
  DWORD dwStringSize;
  DWORD dwStringOffset;
} VARSTRING, *LPVARSTRING;

Members

dwTotalSize

Total size allocated to this data structure, in bytes.

dwNeededSize

Size for this data structure that is needed to hold all the returned information, in bytes.

dwUsedSize

Size of the portion of this data structure that contains useful information, in bytes.

dwStringFormat

Format of the string. This member uses one of the STRINGFORMAT_ Constants.

dwStringSize

Size of the string information, including the null terminator, in bytes.

dwStringOffset

Offset from the beginning of the structure to the variably sized device field containing the string information. The size of the field is specified by dwStringSize.

Remarks

No extensibility.

If a string cannot be returned in a variable structure, the dwStringSize and dwStringOffset members are set in one of the following ways:

  • dwStringSize and dwStringOffset members are both set to zero.
  • dwStringOffset is nonzero and dwStringSize is zero.
  • dwStringOffset is nonzero, dwStringSize is 1, and the byte at the given offset is zero.

Requirements

Requirement Value
Header tapi.h