ECO NUMBER:	 CCAE04062
                -----------
                PRODUCT:	 Compaq C for OpenVMS Alpha
                --------
                UPDATED PRODUCT: Compaq C for OpenVMS Alpha 6.2A
                ----------------
                APPRX BLCK SIZE: 45738
                ----------------
                COMPRESSED KIT CHECKSUM: 3303249264
                ------------------------
                ECO KITS SUPERSEDED BY 
                THIS ECO KIT:              CCAE03062
                                           CCAE02062
                                           CCAE01062
                -----------------------


COVER LETTER for ECO KIT 4 Compaq C Versions 6.2A and 6.2 for OpenVMS Alpha
___________________________________________________________________________


PROBLEM DESCRIPTION:
--------------------
This ECO kit is the first to correct problems in V6.2A.
But because the numbering system for ECO kits is based
on the original parent version, V6.2, it is called
ECO 4.  ECO 3 was the last ECO to V6.2, before the release
of V6.2A.

   o When the return statement of an old-style function definition
     contained a recursive call, the compiler would sometimes
     try to replace the recursive call with a loop construct
     that did not correctly intialize all the loop control elements.
     [First corrected in V6.2A ECO kit 4, compiler ident V6.2-009.]

   o In circumstances that cannot easily be characterized at the
     source code level, optimization of the code generated
     for the va_arg macro (for traversing variable-length
     argument lists) could produce an incorrect result - in
     some cases accessing the argument value following
     the one that should have been accessed.  [First corrected
     in V6.2A ECO kit 4, compiler ident V6.2-009.]

  o The compiler could incorrectly optimize certain loops in which
    computation of the trip count depended on loop bounds and/or
    increments that were run-time expressions that were not made
    into CSEs.  This could manifest either as incorrect code or an
    internal error.  [First corrected in V6.2A, compiler ident
    V6.2-008.]

  o The compiler emits the message bltinimplret by default when
    certain runtime library functions that do not return an int are
    called without including the appropriate header.  This message
    is confusing to many users when it appears in existing
    well-debugged applications.

    The compiler has been changed so that bltinimplret is no longer
    emitted by default, but only when enabled explicitly (or as
    part of the performance or level5 message groups). [This change
    first appeared in ECO kit 3, compiler ident V6.2-007.]

  o Sometimes the compiler may hang when large programs containing
    misaligned data are compiled with the /DEBUG qualifier and
    optimization is not suppressed.

    The compiler now runs to completion in this sitaution.  [This
    problem was fixed in ECO kit 2, compiler ident V6.2-006.]

  o Sometimes the compiler may incorrectly optimize away the
    "store" instruction that performs an assignment to a struct
    member.  The only reliable workaround is to compile
    /NOOPTIMIZE.

    The compiler now produces the correct code to store the values.
    [This problem was fixed in ECO kit 2, compiler ident V6.2-006.]

  o The __CMP_STORE_QUAD built-in function converts its 3rd
    parameter (the new value to be stored) to a signed 32-bit
    value, silently truncating significant bits if passed a value
    not representable as a 32-bit signed int.

    The builtin now properly uses the full 64-bit value. [This
    problem was fixed in ECO kit 1, compiler ident V6.2-005.]

INSTALLATION:
-------------

      Please note that this is not a complete kit.  If you do not
      already have Compaq C V6.2A for OpenVMS Alpha installed on your
      system, please use VMSINSTAL to install CC062 in the usual
      manner before installing this ECO kit.  When installing this
      kit please note that the saveset name is CCAE04062 rather than the
      CC062 saveset name which is specified in the installation guide:

	$ SET DEF SYS$UPDATE
	$ SET PROCESS /PRIV=ALL
	$! if V6.2 not already installed then
	$!     @VMSINSTAL CC062 disk$:[dir]
	$ @VMSINSTAL CCAE04062 disk$:[dir]



  Copyright (c) Compaq Computer Corporation 2000.  All Rights reserved.

  This software is proprietary to and embodies the confidential technology
  of Compaq Computer Corporation.  Possession, use, or copying of this
  software and media is authorized only pursuant to a valid written license
  from Compaq or an authorized sublicensor.

        This ECO has not been through an exhaustive field test process.
        Due to the experimental stage of this ECO/workaround, Compaq
        makes no representations regarding its use or performance.  The
        customer shall have the sole responsibility for adequate protection
        and back-up data used in conjunction with this ECO/workaround.