IX509ExtensionBasicConstraints::InitializeDecode method (certenroll.h)

The InitializeDecode method initializes the extension from a Distinguished Encoding Rules (DER) encoded byte array that contains the extension value. The encoded byte array is represented by a Unicode encoded string.


HRESULT InitializeDecode(
  EncodingType Encoding,
  BSTR         strEncodedData



An EncodingType enumeration value that specifies the type of Unicode encoding applied to the strEncodedData value.


A BSTR variable that contains the DER-encoded extension.

Return value

If the function succeeds, the function returns S_OK.

If the function fails, it returns an HRESULT value that indicates the error. Possible values include, but are not limited to, those in the following table. For a list of common error codes, see Common HRESULT Values.

Return code/value Description
The object is already initialized.


You can use this method if you have a DER-encoded Abstract Syntax Notation One (ASN.1) object that contains a BasicConstraints extension. You must supply the DER-encoded object in a Unicode encoded string. For more information, see the IBinaryConverter interface.

You must call either InitializeEncode or InitializeDecode before you can use an IX509ExtensionBasicConstraints object. The two methods complement each other. The InitializeEncode method enables you to construct a DER-encoded ASN.1 extension object from raw data, and the InitializeDecode method enables you to initialize the raw data from an encoded object.

You can retrieve the following properties for this extension:

  • The Critical property identifies whether the extension is critical. You can also specify this property.
  • The ObjectId property retrieves the object identifier (OID).
  • The IsCA property identifies whether the certificate subject can be a certification authority.
  • The PathLenConstraint property identifies the depth of the subordinate certification authority chain.


Minimum supported client Windows Vista [desktop apps only]
Minimum supported server Windows Server 2008 [desktop apps only]
Target Platform Windows
Header certenroll.h
DLL CertEnroll.dll

See also