BUILD_DEFINES

============================
BUILD Defines/Defaults
============================

This file lists several of the preprocessor definitions used to
conditionally compile functionality in the code.  It also lists
their defaults, and identifies how/when they are set.


Contents
1. MANUALLY configured in build (MAKEFILE DEF switches)
   a. IMPLEMENTATION SPECIFIC OPTIONS
   b. EXPERIMENTAL EXTENSION OPTIONS
2. AUTO configured either in the code or based on environment in build


===================================================================
1. MANUALLY configured in build (MAKEFILE DEF switches)
===================================================================
The preprocessor definitions listed in this section can be manually
enabled or commented out in the concerto/target.mak file before
performing a clean build.


OFFICIAL KHR EXTENSION OPTIONS:
--------------------------------
Definitions in this section include Khronos-approved extensions.

OPENVX_USE_IX (ENABLED)
- Enables the import/export extension

OPENVX_USE_NN (ENABLED)
- Enables the neural network extension

OPENVX_USE_USER_DATA_OBJECT (ENABLED)
- Enables the user data object extension

OPENVX_USE_PIPELINING (DISABLED)
- Enables the pipelining extension

OPENVX_USE_STREAMING (DISABLED)
- Enables the streaming extension

IMPLEMENTATION SPECIFIC OPTIONS:
--------------------------------
Definitions in this section include user preference options and
Khronos-approved extensions (in at least the provisional state).

OPENVX_BUILDING (ENABLED)
- Defines the VX_API_ENTRY macro to be a dllexport attribute.
- If disabled, the VX_API_ENTRY macro is defined to be a dllimport attribute.

OPENVX_USE_SMP (ENABLED)
- Enables use of threadpool, so that threads can execute parallel work
  on different cores.

OPENVX_USE_TILING (DISABLED)
- Enables tiling extension (Provisional spec released)


EXPERIMENTAL EXTENSION OPTIONS:
-------------------------------
Definitions in this section are for features which have had little to
no discussion or debate by the Khronos OpenVX working group.  As such,
they are not verified and are subject to change considerably or potentially
be removed.  When discussion on a proposed extension becomes mature,
then it may be moved to the "IMPLEMENTATION SPECIFIC" category above or
added to a new revision of the specification.

EXPERIMENTAL_USE_DOT (ENABLED in Android, LINUX, and DARWIN only)
- Enables DOT extension proposal

OPENVX_USE_S16 (DISABLED)
- Enables s16 extension proposal
- Currently only used in extension list
- Needs to be added to code that is allowing S16 in the sample
  implementation (eg. absdiff).

EXPERIMENTAL_PLATFORM_SUPPORTS_16_FLOAT (DISABLED)
- defines a scalar type vx_float16, if platform supports it (otherwise,
  no type is defined)


===================================================================
2. AUTO configured either in the code or based on environment in build
===================================================================
The preprocessor definitions listed in this section are automatically
enabled or disabled based on other options or environment settings.

OPENVX_TILING_1_0 (ENABLED in code when OPENVX_USE_TILING is defined)
- Sets the version of tiling spec

OPENVX_USE_XML (AUTO-build)
- Automatically enabled if $XML_PKG is defined in LINUX build
  environment (usually export XML2_PKG=libxml-2.0 in Ubuntu after dev
  version is installed), or libxml2 is installed on DARWIN.
- If defined, (if $XML2_PKG is in env), the xml import/export
  functions are compiled and the associated tests in the vx_tests exe
  are compiled.

OPENVX_USE_SDL (AUTO-build)
- Automatically enabled if $SDL_PKG is defined in build environment
- If defined, (if $SDL_PKG is in env), vx_cam_test is added to build,
  otherwise, vx_cam_test is not built.


OPENVX_USE_C99 (AUTO-code)
- AUTO ENABLE on PLATFORM:
  #if __STDC_VERSION__ >= 199901L
  #define OPENVX_USE_C99
  #endif
- Only relevant in vx_matrix_access.c, for 2D f32 matrices.