release-notes.txt

UPC Language Specification (version 1.3)

Release Notice

Date: November 16, 2013

Background
----------

During the course of the past two years, a group of UPC compiler
vendors, users, and programming language experts (known as the
UPC Consortium) has convened for the purpose of updating the
UPC (Unified Parallel C) language specification.

The prior UPC language specification (version 1.2) was ratified
several years ago (2005).  The recent effort to update the
UPC language specification incorporated both compiler
development experience and user experience to improve the precision
of the standard and to define new library capabilities that 
provide facilities which are often required when implementing
parallel programming solutions in UPC.

UPC Specification Version 1.3
-----------------------------

The UPC version 1.3 specification consists of three documents:

* UPC Language Specifications, v1.3
   Specifies the UPC language and core libraries
   
* UPC Required Library Specifications, v1.3
   Specifies library extensions provided by all compliant UPC compilers
   
* UPC Optional Library Specifications, v1.3
   Specifies experimental library extensions, which might be omitted
   in some UPC implementations
   
Each document is available in both an official normative format, 
and a draft format showing change annotations relative to the prior UPC 1.2 spec.
   
All UPC specification documents are publicly and freely available at:
 http://upc-lang.org
or alternatively from:
 http://code.google.com/p/upc-specification/downloads/list


Change History
--------------

Final
*****

Issue #112:     Removing implicit phase reset for pointer-to-shared-array casting/assignment 
                with differing referent type but matching ultimate element type

Issue #116:     Correct UPC_CHAR to be a 'signed' char

Draft 4
*******

Issue  #3:	Clarifying pointers to shared arrays, and multi-D shared arrays

Issue  #50:	Clarification: overlapping memory copies undefined by presence of "restrict" keyword

Issue  #88:	Nested upc_forall semantics 

Issue  #94:	Clarification: dynamic threads and the constraint 
                "when multiplied by an integer expression"
                
Issue  #95:	Clarification: can THREADS appear more than once 
                in a PTS typedef (in a dynamic threads environment)?
                
Issue  #96:	upc_all_(prefix_)reduce: behavior is under-specified for floating-point NaNs

Issue  #102:	Update community URL and introduction/acknowledgement sections

Issue  #104:	Clarify relational operators (>,<,>=,<=) applied to PTS operands

Issue  #106:	Clarify contiguity of local slice of a shared array

Issue  #110:	Clarify interaction of shared with effective type for accesses

Issue  #111:	UPC_CASTABLE flags underspecified

Draft 3
*******

Issue  #7: Library: Atomic Memory Operations (AMO)
           (This library was added to the optional library)

Issue  #10: Add upc_types.h to define common library types

Issue  #12: Library: Collective Deallocation Functions
           (These library functions were added to the core library)

Issue  #15: Add constraint: a declaration of an array with indefinite block size
            must have compile-time constant dimensions

Issue  #29: Correct example 2 in the UPC specification in the discussion of
            upc_forall

Issue  #37: Library: Shared-pointer privatizability (castability) functions
           (This library was added to the optional library)
           
Issue  #41: Library: non-blocking memory copy extensions
           (This library was added to the optional library)
           
Issue  #54: Write section "Proposed Additions and Extensions"

Issue  #58: Bring Conformance section into agreement with the C99 specification

Issue  #59: The affinity test on integer values in a upc_forall statement is
            undefined for negative values

Issue  #64: Barrier statement optional expression type is an integer type, not
            just ’int’

Issue  #65: Define a null pointer-to-shared in terms of C99’s "null pointer constant"

Issue  #70: Clarification: how is type compatibility defined when one/both
            pointer-to-shared target types are incomplete?

Issue  #71: Clarification: can the [*] layout qualifier be applied to a typedef?

Issue  #78: Remove shared array initialization

Issue  #91: Library section boilerplate spec text

Issue #100: Update introduction section

Draft 2
*******

Issue  #4: Progress guarantee of upc_notify and upc_wait

Issue  #9: Library: High-Performance Wall-Clock Timers (upc_tick_t)
           (This timer library was added as a required library)

Issue #32: modification: THREADS/MYTHREAD have "integral value"
           rather than "type int"

Issue #33: clarification: MYTHREAD and THREADS are expressions
           (cannot assign to or take address of them)

Issue #49: clarification: unlock of freed lock

Issue #51: clarification: revise text to eliminate an ambiguity
           in barrier matching semantics

Issue #55: Miscellaneous specification document typographical errors

Issue #82: Remove the deprecated upc_local_alloc function

Issue #83: Strengthen the "default" pragma from "implementation-defined"
           to "relaxed"


UPC Language Specification Review Process
-----------------------------------------

To learn more about planned changes or to participate in the UPC
specification revision process, please visit:
http://code.google.com/p/upc-specification

If you would like to participate in the specification review
process by contributing your time and effort to the various writing
and editorial tasks, please contact Gary Funck at <gary@intrepid.com>
or Yili Zheng at <yzheng@lbl.gov>.