aq06930_.htm |
Last updated Friday, 21 July 2017The MQRFH2 header contains information about the structure of a message, and its intended consumers, to enable a message broker to process the message and deliver or publish the message to those consumers.
The value 'MQHRF2 ' should be put in the Format field of the preceding header (usually the MQMD). The constant MQFMT_RF_HEADER_2 is defined with this value.
For the C programming language, the constant MQFMT_RF_HEADER_2_ARRAY is also defined. This constant has the same value as MQFMT_RF_HEADER_2, but it is an array of characters, not a character string.
The character set and encoding of the fields in the MQRFH2 header are as follows:
Some character sets have a representation that is dependent on the encoding. If NameValueCCSID defines one of these character sets, NameValueData must be in the same encoding as the other fields in the MQRFH2 header.
The MQRFH2 header contains the following fields:
| Field Name | Description | Details |
|---|---|---|
| StrucId | Structure identifier | The value must be MQRFH_STRUC_ID, which is the identifier for the rules and formatting header structure,. IBM® Integration Bus populates this field for you if you are constructing an MQRFH2 header in a message flow. For the C programming language, the constant MQRFH_STRUC_ID_ARRAY is also defined; this constant has the same value as MQRFH_STRUC_ID, but it is an array of characters, not a character string. |
| Version | Structure version number | The value must be MQRFH_VERSION_2, which is the Version-2 rules and formatting header structure. |
| Struclength | Total length of MQRFH2 (including NameValueData) | The initial value of this field is MQRFH_STRUC_LENGTH_FIXED_2, which is the length of the fixed part of the MQRFH2 header structure. This is the length in bytes of the MQRFH2 header structure, including any NameValueLength and NameValueData fields at the end of the structure. IBM Integration Bus populates this field for you if you are constructing an MQRFH2 header in a message flow. There might be more than one pair of these fields at the end of the structure, in the sequence: length1, data1, length2, data2, ....... The length of any user data that follows the last NameValueData field at the end of the structure is not included in StrucLength. Note: If Struclength is not a multiple
of four, problems might occur with the data conversion of user data
in some operating system environments.
|
| Encoding | Numeric encoding of data that follows NameValueData | The initial value of this field is MQENC_NATIVE. This field specifies how numeric values in any data that follows the last NameValueData field are represented. This applies to binary integer data, packed decimal integer data and floating-point data. |
| CodedCharSetId | Character set identifier of data that follows NameValueData | The initial value of this field is MQCCSI_INHERIT, which means that the character set identifier is the same as that of the current structure. This field identifies the coded character set for any character strings in the data that follows the last NameValueData field. |
| Format | Format name of data that follows NameValueData | The initial value of this field is MQFMT_NONE. This field specifies the format name of any data that follows the last NameValueData field. The name should be padded with blanks to the length of the field. Note: Do not use a null character to terminate the name before
the end of the field; the queue manager does not change to a blank
character the null character, or any characters that follow the null
character, in the MQRFH2 header.
Note: Do not specify
a name with leading or embedded blank characters.
|
| Flags | Flags | The initial value of this field is MQRFH_NONE, which means that there are no flags. |
| NameValueCCSID | Character set identifier of NameValueData | The initial value of this field is 1208, which means that the UTF-8 coded character set is used. This field identifies the coded character set for data in the NameValueData field. This is different from the character set for other character strings in the MQRFH2 header structure, and might be different from the character set for any character data that follows the last NameValueData field. NameValueCCSID must have one of the following values: 1200: UCS-2 open-ended 1208: UTF-8 13488: UCS-2 2.0 subset 17584: UCS-2 2.1 subset (includes the euro symbol €) For the UCS-2 character sets, the encoding (byte order) of the NameValueData field must be the same as the encoding of the other fields in the MQRFH2 header structure. Note: Surrogate characters (X'D800'
thru X'DFFF') are not supported.
|
The following two fields are optional, but if present they must occur as a pair. They can be repeated as a pair as many times as required. If these fields occur more than once, they must occur in the sequence ..... length1, data1, length2, data2, ....... |
||
| NameValueLength | Length of NameValueData | This field specifies the length, in bytes, of the NameValueData field that follows this field. IBM Integration Bus populates this field for you if you are constructing an MQRFH2 header in a message flow. Note: If NameValueLength is
not a multiple of four, there might be a problem with the conversion
of the data that follows the NameValueData field.
|
| NameValueData | This is a variable-length character string containing data that is encoded using an XML-like structure | The length, in bytes, of this string is given by the NameValueLength field that precedes this NameValueData field. To avoid the problem described in the note accompanying the description of the NameValueLength field, either extend this field with blanks so that its length is a multiple of four, or terminate the field with a null character. |
typedef struct tagMQRFH2 {
MQCHAR4 StrucId; /* Structure identifier */
MQLONG Version; /* Structure version number */
MQLONG StrucLength; /* Total length of MQRFH2 including
NameValueData */
MQLONG Encoding; /* Numeric encoding of data that follows
NameValueData */
MQLONG CodedCharSetId; /* Character set identifier of data that
follows NameValueData */
MQCHAR8 Format; /* Format name of data that follows
NameValueData */
MQLONG Flags; /* Flags */
MQLONG NameValueCCSID; /* Character set identifier of NameValueData */
} MQRFH2;