C language data types

This section contains information on the following data types used in the WebSphere MQ Everyplace C client:

Primitive

The following platform-independent primitive data types are used throughout the C native APIs of WebSphere MQ Everyplace:


Typedef name Size (no. of bytes) Alignment Equivalent C data type Equivalent Java data type
MQEBYTE 1 byte Unsigned char n/a
MQECHAR 1 byte char byte
MQEINT32 4 Even-byte long int
MQEINT64 8 Even-byte longlong long
PMQE* 4 Even-byte "*" n/a.
MQEH* 4 Even-byte long n/a

MQEHANDLE_NULL represents an invalid handle value for all handle types and functions that return handle values may return this value when an error occurs.

Endian

The endian of the data types is platform-dependent. For example, on an x86 based machine a multibytes data type is ordered in little-endian, the least-significant byte occupies the lower memory address. The opposite is true on a big-endian 68k based machine. The data on a transmission medium is always big endian.

MQeFields data types

The following MQeFields data types are provided with WebSphere MQ Everyplace:

Fields data type Size in bytes
MQETYPE_UNTYPED n/a
MQETYPE_ASCII 1
MQETYPE_UNICODE 2
MQETYPE_BOOLEAN 1
MQETYPE_BYTE 1
MQETYPE_SHORT 2
MQETYPE_INT 4
MQETYPE_LONG 8
MQETYPE_FLOAT 4
MQETYPE_DOUBLE 8
MQETYPE_ARRAYELEMENTS 4
MQETYPE_FIELDS 4



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