V4 Requirements for Standard Types

The purpose of this page is to discuss and agree on a set of standard basic data types that will be supported throughout EPICS V4. As at 2005-5-19 the latest implementation of Data Access doesn't support all the types that the V4 database is proposed to support; we should try to converge on a common set.

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epicsTypes.h

This header will include a set of typedefs (OS dependent if necessary) as follows:

epicsInt16

A signed (2s-complement) 16-bit integer type.

epicsUint16

An unsigned 16-bit integer type.

epicsInt32

A signed (2s-complement) 32-bit integer type.

epicsUint32

An unsigned 32-bit integer type.

epicsInt64

A signed (2s-complement) 64-bit integer type.

epicsUint64

An unsigned 64-bit integer type.

epicsFloat32

A 32-bit IEEE floating-point numeric type.

epicsFloat64

A 64-bit IEEE floating-poing numeric type.

epicsOctet

An (unsigned?) 8-bit character type. This is not intended for numeric operations, just for use when storing and manipulating UTF-8 encoded character strings.

epicsString

A UTF-8 encoded Unicode character string.

Since this type does not map directly to any native C/C++ type, we're going to have to discuss the implementation and facilities we'll provide. Marty has a proposal for an implementation taking into account Jeff's ideas and the requirements of character encoding conversions that I'll link to here when it's ready for public consumption.