Elementary data types

The MQBOOL data type represents a boolean value. The value 0 represents false. Any other value represents true. An MQBOOL must be aligned as for the MQLONG data type.

The MQBYTE data type represents a single byte of data. No particular interpretation is placed on the byte; it is treated as a string of bits, and not as a binary number or character. No special alignment is required.

When MQBYTE data is sent between queue managers that use different character sets or encodings, the MQBYTE data is not converted in any way. The MsgId and CorrelId fields in the MQMD structure are like this.

An array of MQBYTE is sometimes used to represent an area of main storage that is not known to the queue manager. For example, the area might contain application message data or a structure. The boundary alignment of this area must be compatible with the nature of the data contained within it.

In the C programming language, any data type can be used for function parameters that are shown as arrays of MQBYTE. This is because such parameters are always passed by address, and in C the function parameter is declared as a pointer-to-void.

Each MQBYTEn data type represents a string of n bytes, where n can take any of the following values: 8, 16, 24, 32, 40, or 128. Each byte is described by the MQBYTE data type. No special alignment is required.

If the data in the byte string is shorter than the defined length of the string, the data must be padded with nulls to fill the string.

When the queue manager returns byte strings to the application (for example, on the MQGET call), the queue manager pads with nulls to the defined length of the string.

Named constants are available to define the lengths of byte string fields. These are listed in Constants

The MQCHAR data type represents a single-byte character, or one byte of a double-byte or multi-byte character. No special alignment is required.

When MQCHAR data is sent between queue managers that use different character sets or encodings, the MQCHAR data usually requires conversion in order for the data to be interpreted correctly. The queue manager does this automatically for MQCHAR data in the MQMD structure. Conversion of MQCHAR data in the application message data is controlled by the MQGMO_CONVERT option specified on the MQGET call; see the description of this option in MQGMO - Get-message options for further details.

Each MQCHARn data type represents a string of n characters, where n can take any of the following values: 4, 8, 12, 20, 28, 32, 48, 64, 128, or 256. Each character is described by the MQCHAR data type. No special alignment is required.

If the data in the string is shorter than the defined length of the string, the data must be padded with blanks to fill the string. In some cases a null character can be used to end the string prematurely, instead of padding with blanks; the null character and characters following it are treated as blanks, up to the defined length of the string. The places where a null can be used are identified in the call and data type descriptions.

When the queue manager returns character strings to the application (for example, on the MQGET call), the queue manager always pads with blanks to the defined length of the string; the queue manager does not use the null character to delimit the string.

Named constants are available that define the lengths of character string fields and are listed in Constants.

The MQFLOAT32 data type is a 32-bit floating-point number represented using the standard IEEE floating-point format. An MQFLOAT32 must be aligned on a 4-byte boundary.

The use of MQFLOAT32 in C on z/OS requires the use of the FLOAT(IEEE) compiler flag.

The use of MQFLOAT32 in COBOL is limited to compilers that support floating-point numbers in IEEE format. This might require the use of the FLOAT(NATIVE) compiler flag.

The MQFLOAT64 data type is a 64-bit floating-point number represented using the standard IEEE floating-point format. An MQFLOAT64 must be aligned on an 8-byte boundary.

The use of MQFLOAT64 in C on z/OS requires the use of the FLOAT(IEEE) compiler flag.

The use of MQFLOAT64 in COBOL is limited to compilers that support floating-point numbers in IEEE format. This might require the use of the FLOAT(NATIVE) compiler flag.

The MQHCONFIG data type represents a configuration handle, that is, the component that is being configured for a particular installable service. A configuration handle must be aligned on its natural boundary.

Applications must not rely on the format of the data stored inside this handle. If valid, its value is intended to be usable in further MQI calls, but is not intended to have any meaning besides that purpose.

The MQHCONN data type represents a connection handle, that is, the connection to a particular queue manager. A connection handle must be aligned on a 4-byte boundary.

Applications must not rely on the format of the data stored inside this handle. If valid, its value is intended to be usable in further MQI calls, but is not intended to have any meaning besides that purpose.

The MQHMSG data type represents a message handle that gives access to a message. A message handle must be aligned on an 8-byte boundary.

Applications must not rely on the format of the data stored inside this handle. If valid, its value is intended to be usable in further MQI calls, but is not intended to have any meaning besides that purpose.

The MQHOBJ data type represents an object handle that gives access to an object. An object handle must be aligned on a 4-byte boundary.

Applications must not rely on the format of the data stored inside this handle. If valid, its value is intended to be usable in further MQI calls, but is not intended to have any meaning besides that purpose.

The MQINT32 data type is a 32-bit signed binary integer that can take any value in the range -2 147 483 648 through +2 147 483 647, unless otherwise restricted by the context.

See the definition of MQLONG.

The MQINT64 data type is a 64-bit signed integer that can take any value in the range -9 223 372 036 854 775 808 through +9 223 372 036 854 775 807, unless otherwise restricted by the context.

For COBOL, the valid range is limited to -999 999 999 999 999 999 through +999 999 999 999 999 999. A 64-bit integer must be aligned on an 8-byte boundary.

The MQLONG data type is a 32-bit signed binary integer that can take any value in the range -2 147 483 648 through +2 147 483 647, unless otherwise restricted by the context.

For COBOL, the valid range is limited to -999 999 999 through +999 999 999. An MQLONG must be aligned on a 4-byte boundary.

The IBM MQ process identifier.

This is the same identifier used in MQ trace and FFST™ dumps, but might be different from the operating system process identifier.

The MQPTR data type is the address of data of any type. A pointer must be aligned on its natural boundary; this is a 16-byte boundary on IBM i, and an 8-byte boundary on other platforms.

Some programming languages support typed pointers; the MQI also uses these in a few cases (for example, PMQCHAR and PMQLONG in the C programming language).

The IBM MQ thread identifier.

This is the same identifier used in MQ trace and FFST™ dumps, but might be different from the operating system thread identifier.

The MQUINT32 data type is a 32-bit unsigned binary integer.

See the definition of MQULONG.

The MQINT64 data type is a 64-bit unsigned integer that can take any value in the range 0 through +18 446 744 073 709 551 615, unless otherwise restricted by the context.

For COBOL, the valid range is limited to 0 through +999 999 999 999 999 999. A 64-bit integer must be aligned on an 8-byte boundary.

The MQULONG data type is a 32-bit unsigned binary integer that can take any value in the range 0 through +4 294 967 294, unless otherwise restricted by the context.

For COBOL, the valid range is limited to 0 through +999 999 999. An MQULONG must be aligned on a 4-byte boundary.