UT_EnvControl.h

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/*
 * PROPRIETARY INFORMATION.  This software is proprietary to
 * Side Effects Software Inc., and is not to be reproduced,
 * transmitted, or disclosed in any way without written permission.
 *
 * NAME:        UT_EnvControl.h ( UT Library, C++)
 *
 * COMMENTS:    In Houdini applications, there are many environment variables
 *              which control the behaviour of certain features/capabilities.
 *              This class provides a centralized place to efficiently query
 *              these variables.  The reason for the centralization is so that
 *              we can easily get a list of these control variables.  As well,
 *              this mechanism provides ways of changing the control settings
 *              from environment variables to disk file to registry entry.
 *              Currently only environment variable control is supported.
 *
 *
 *   When adding a new environment variable, please document the variable in
 *   $SHD/ref/env.txt
 */

#ifndef __UT_EnvControl__
#define __UT_EnvControl__

#include "UT_API.h"
#include "UT_StringHolder.h"
#include <SYS/SYS_Allocator.h>
#include <SYS/SYS_StaticAssert.h>
#include <SYS/SYS_Types.h>

class UT_StringArray;
class UT_Variant;

namespace UT_Package
{
    class Loader;
    class Package;
}

// This define declares a fixed size of array for holding our cached
// environment variable values. It should be larger than any of our actual
// requirements so that we can add new enum values to the end of these
// tables without breaking ABI compatibility (as long as we don't actually
// exceed this value and need to increase it).
#define MAX_CONTROLS_WITH_BUFFER 512

enum UT_IntControl
{
    // UT library: Public interface
    ENV_HOUDINI_WINDOW_CONSOLE,
    ENV_HOUDINI_CONSOLE_LINES,
    ENV_HOUDINI_DISABLE_CONSOLE,
    ENV_HOUDINI_TEXT_CONSOLE,
    ENV_HOUDINI_VERBOSE_ERROR,
    ENV_HOUDINI_DISABLE_FILE_LOAD_WARNINGS,
    ENV_HOUDINI_INTERRUPT_THRESH,
    ENV_HOUDINI_REALTIME_INTERRUPT_THRESH,
    ENV_HOUDINI_OLD_SPINNER,
    ENV_HOUDINI_HSERVER_PORT,
    ENV_HOUDINI_DISABLE_CPUID,
    ENV_HOUDINI_DISABLE_MMX,
    ENV_HOUDINI_DISABLE_XMMX,
    ENV_HOUDINI_DISABLE_SSE,
    ENV_HOUDINI_DISABLE_3DNOW,
    ENV_HOUDINI_DISABLE_AVX,
    ENV_HOUDINI_OSX_SWAP_DEL_AND_BACKSPACE,

    // UT: Internal controls
    ENV_HOUDINI_COREDUMP,
    ENV_HOUDINI_UI_COREDUMP,
    ENV_HOUDINI_SYSTRACE,
    ENV_HOUDINI_ENABLE_UNDO_LOG,
    ENV_HOUDINI_INTERRUPT_DEBUG,
    ENV_HOUDINI_INTERRUPT_KEY,
    ENV_HOUDINI_NO_ASSERTS,
    ENV_HOUDINI_INTERACTIVE_ASSERTS,
    ENV_HOUDINI_INTERACTIVE_ASSERTS_TRACE,
    ENV_HOUDINI_ACCESS_METHOD,
    ENV_HOUDINI_CONNECTIONS_DEBUG,

    // Houdini Environment File Control
    ENV_HOUDINI_NO_ENV_FILE_OVERRIDES,
    ENV_HOUDINI_NO_ENV_FILE,

    // FS: Public interface
    ENV_HOUDINI_DSO_ERROR,
    ENV_HOUDINI_DSO_DEEPBIND,
    ENV_HOUDINI_CPP_EXPAND_PRAGMA,
    ENV_HOUDINI_ANONYMOUS_STATISTICS,
    ENV_HOUDINI_ANONYMOUS_STATISTICS_UPLOAD_ERRORS,
    ENV_HOUDINI_PROMPT_ON_CRASHES,
    ENV_HOUDINI_MAX_DESCRIPTORS,

    // GA: Public interface
    ENV_HOUDINI_GEOMETRY_CACHESIZE,

    // IMG3D: Public interface
    ENV_HOUDINI_TEX3D_USAGE,

    // IMG: Public interface
    ENV_HOUDINI_CINEON_WHITE_POINT,
    ENV_HOUDINI_CINEON_BLACK_POINT,
    ENV_HOUDINI_CINEON_FULL_RANGE,
    ENV_HOUDINI_TIFF_SAMPLEFORMAT,
    ENV_HOUDINI_TIFF_BOTTOMLEFT,
    ENV_HOUDINI_DISABLE_IMAGE_DSO,
    ENV_HOUDINI_RAT_USAGE,
    ENV_HOUDINI_RAT_MEMORY,
    ENV_HOUDINI_RAT_FILES,
    ENV_HOUDINI_RAT_STREAMS_PER_FILE,
    ENV_HOUDINI_RAT_TILESIZE,
    ENV_HOUDINI_RAT_LOCALCACHE,
    ENV_HOUDINI_RAT_OPTIMIZE_BANDWIDTH,
    ENV_HOUDINI_RAT_MAX_MIP_RES,
    ENV_HOUDINI_PTEX_USAGE,
    ENV_HOUDINI_PTEX_FILES,
    ENV_HOUDINI_PTEX_WINDING,
    ENV_HOUDINI_UVENLARGER_DIFFUSE_WRAP,
    ENV_HOUDINI_THREAD_IMAGE,
    ENV_HOUDINI_MDISPLAY_WAIT,
    ENV_HOUDINI_IMAGE_DEBUG,
    ENV_HOUDINI_TARGA_LINEAR,
    ENV_HOUDINI_ENABLE_EXR_TEXTURE,
    ENV_HOUDINI_OIIO_EXR,
    ENV_HOUDINI_OIIO_MAX_STAT_LENGTH,
    ENV_HOUDINI_OIIO_DDS,
    ENV_HOUDINI_TEXTURE_COMPRESS,
    ENV_HOUDINI_COLOR_MANAGER,
    // IMG: Private interface
    ENV_HOUDINI_MIP_READ,
    ENV_HOUDINI_FB_FILTER_ORIGINAL,
    ENV_HOUDINI_SOCKET_PORT,
    ENV_HOUDINI_AUDIT_IO,
    ENV_HOUDINI_OLD_RATS,
    ENV_HOUDINI_RAT_VERSION,
    ENV_HOUDINI_OCIO_FILENAME_COLORSPACE,
    ENV_HOUDINI_OCIO_NANOCOLOR_NAMES,
    ENV_HOUDINI_OCIO_TEXTURE_WARNINGS,

    // MV: Public interface
    ENV_HOUDINI_QTML_USE_GDI,

    // VEX: Public interface
    ENV_HOUDINI_VEX_DISABLE_AUTO_FOLDING,
    ENV_HOUDINI_VEX_DISABLE_INSTANCE_CACHE,
    ENV_HOUDINI_VEX_DISABLE_JIT,
    ENV_HOUDINI_VEX_PROFINFO,
    ENV_HOUDINI_VEX_PROFINFO_HTML,
    ENV_HOUDINI_VEX_BUILTIN_BSDF,
    ENV_HOUDINI_VEX_ASSERT,
    ENV_HOUDINI_VEX_MODULECACHESIZE,
    ENV_HOUDINI_VEX_RETURNBYREFERENCE,
    ENV_HOUDINI_VEX_MEMORYCACHESIZE,

    // VEX: Private interface
    ENV_HOUDINI_VEX_URANDOM,

    // RE: Public interface
    ENV_HOUDINI_OVERRIDE_XRES,
    ENV_HOUDINI_OVERRIDE_YRES,
    ENV_HOUDINI_UISCALE,
    ENV_HOUDINI_OGL_ERROR_CHECK,
    ENV_HOUDINI_OGL_DUMP_SHADER_ERRORS,
    ENV_HOUDINI_OGL_DEBUG,
    ENV_HOUDINI_OGL_ENABLE_TEXTURE_SEQUENCES,
    ENV_HOUDINI_OGL_CORE_PROFILE,
    ENV_HOUDINI_ENABLE_RETINA,
    ENV_HOUDINIX_ENABLE_RETINA_EDR,

    // CMD
    ENV_HOUDINI_HIP_FROM_PATH,
    ENV_HOUDINI_SET_PWD_TO_HIP,

    // OP
    ENV_HOUDINI_NO_EXPORT_RENAME,
    ENV_HOUDINI_SCRIPT_DEBUG,
    ENV_HOUDINI_COOK_MODE_THRESHOLD,

    // GEO
    ENV_HOUDINI_RMAN_CURVE_STEP,
    ENV_HOUDINI_DISABLE_ALEMBIC_INDEXED_ARRAYS,
    ENV_HOUDINI_ALEMBIC_OGAWA_STREAMS,

    // GU
    ENV_HOUDINI_GU_DEBUG,

    // RAY
    ENV_MANTRA_FORCE_RAY,
    ENV_MANTRA_NOFOGBOX,
    ENV_MANTRA_BIAS_NORMAL,
    ENV_MANTRA_DEBUGMEMORY,
    ENV_MANTRA_NONRAT_ERROR,
    ENV_MANTRA_LINEAR_CREASES,
    ENV_MANTRA_INTERNAL_RUNLIMIT,
    ENV_MANTRA_THREADED_REFINE,
    ENV_MANTRA_RENDERSTATE_STRIP_SPLITS,
    ENV_MANTRA_VECTOR_BIND_MODE,

    ENV_KARMA_DEBUG_FORCE_IPR,
    ENV_KARMA_DEBUG_CHECKPOINT,
    ENV_KARMA_PRUNE_PRIMVARS,
    ENV_KARMA_GEOLIGHT_PARTIAL_OPACITY,
    ENV_KARMA_ENABLE_ZNORMAL_COMPRESSION,
    ENV_KARMA_ZNORMAL_MINSIZE,

    ENV_KARMA_XPU_DISABLE_OPTIX_DEVICE,
    ENV_KARMA_XPU_DISABLE_EMBREE_DEVICE,
    ENV_KARMA_XPU_DISABLE_DEVICE_0,
    ENV_KARMA_XPU_DISABLE_DEVICE_1,
    ENV_KARMA_XPU_DISABLE_DEVICE_2,
    ENV_KARMA_XPU_DISABLE_DEVICE_3,
    ENV_KARMA_XPU_DISABLE_DEVICE_4,
    ENV_KARMA_XPU_DISABLE_MIPMAPS,
    ENV_KARMA_XPU_MAX_SHADER_TEXTURE_RES,
    ENV_KARMA_XPU_MAX_LIGHTING_TEXTURE_RES,
    ENV_KARMA_XPU_MAX_UDIM_U,
    ENV_KARMA_XPU_MAX_UDIM_V,
    ENV_KARMA_XPU_MAX_UNIFORM_VOLUME_SPANS,
    ENV_KARMA_XPU_NUM_PER_DEVICE_BLENDING_THREADS,
    ENV_KARMA_XPU_THREAD_COMPILE,
    ENV_KARMA_XPU_OPTIX_FORCE_CONSTANT_FOLDING,
    ENV_KARMA_XPU_OPTIX_CURVE_OPT_LEVEL,
    ENV_KARMA_XPU_OPTIX_HQ_LINEAR_FILTERING,
    ENV_KARMA_XPU_OPTIX_SPARSE_TEXTURES,
    ENV_KARMA_XPU_OPTIX_ENABLE_MEMORY_RESOURCE,
    ENV_KARMA_XPU_OPTIX_DISABLE_HOST_PINNED,
    ENV_KARMA_XPU_ENABLE_NEW_TEXBLUR_BEHAVIOR,

    ENV_HOUDINI_DEBUG_OPTIX_DENOISE,
    ENV_HOUDINI_DEBUG_OPTIX_GTGPUTRACE,

    // COP2
    ENV_HOUDINI_COP_ENSURECOLORPLANES,
    ENV_HOUDINI_COP_MAXRES,

    // IFD
    ENV_HOUDINI_RMAN_INCLUDE_FIX,
    ENV_HOUDINI_MI_DONT_FLIP_RMAP,
    ENV_HOUDINI_DISABLE_SOHO_SPOOLING,

    // MAT
    ENV_HOUDINI_DISABLE_SAVE_THUMB,

    // UI
    ENV_HOUDINI_UI_DEBUG,
    ENV_HOUDINI_QT_DEBUG,
    ENV_HOUDINI_ENABLE_FPS_SCALE,
    ENV_HOUDINI_DISABLE_FPS_MAINTAIN_FSTART,
    ENV_HOUDINI_UI_QUEUE_SIZE,
    ENV_HOUDINI_UI_QUEUE_DEBUG,
    ENV_HOUDINI_X11_SYNCHRONOUS,
    ENV_HOUDINI_WRITE_BINARY_ICONS,
    ENV_HOUDINI_NO_SPLASH,
    ENV_HOUDINI_NO_START_PAGE_SPLASH,
    ENV_HOUDINI_ENABLE_TABLET,
    ENV_HOUDINI_ENABLE_WINTAB,
    ENV_HOUDINI_USE_NATIVE_FILE_CHOOSER,
    ENV_HOUDINI_MAX_FILE_HISTORY,
    ENV_HOUDINI_FONT_RENDERING,
    ENV_HOUDINI_RUN_IN_FOREGROUND,
    ENV_HOUDINI_UI_USE_RADIALMENU_MASKS,
    ENV_HOUDINI_DISABLE_HUD,
    ENV_HOUDINI_DISABLE_VIEWER_MESSAGES,
    ENV_HOUDINI_NO_EXTERNAL_ICON_CACHE,
    ENV_HOUDINI_ANIM_ENABLE_GPU_ACCELERATION,
    ENV_HOUDINI_PLAYBAR_SNAP_TIME_TO_EARLIER_FRAME,

    ENV_HOUDINI_INTERNAL_IS_UI_REG_TEST,
    ENV_HOUDINI_INTERNAL_USE_NEW_UI,
    ENV_HOUDINI_INTERNAL_USE_PYTHON_QSTYLE,

    ENV_HOUDINI_INTERNAL_NO_MACOS_MENU_BAR,

    // OPUI
    ENV_HOUDINI_PERFORMANCE_SIZE,
    ENV_HOUDINI_BUFFEREDSAVE,
    ENV_HOUDINI_HIPEXT,
    ENV_HOUDINI_ENABLE_OLD_PRESETS,
    ENV_HOUDINI_USE_OTL_AS_DEFAULT_HDA_EXT,

    // DM
    ENV_HOUDINI_SKIP_NAME,
    ENV_HOUDINI_OGL_FILECOUNT,
    ENV_HOUDINI_SET_PIVOT_LEGACY_CENTER,

    // MATUI
    ENV_HOUDINI_TOP_POS_SINGLE_PASS,

    // Custom
    ENV_HOUDINI_COP_TESTFRACTION,
    ENV_HOUDINI_ABEKAS_PAL_XRES,
    ENV_HOUDINI_ABEKAS_PAL_YRES,
    ENV_HOUDINI_IPLAY_IP,

    // LM
    ENV_HOUDINI_NOHKEY,
    ENV_HOUDINI_NOHKEY_APPRENTICE,
    ENV_HOUDINI_NOHKEY_LOGIN,
    ENV_HOUDINI_NOHKEY_LOGIN_RELAUNCH,
    ENV_HOUDINI_LICTEST,
    ENV_HOUDINI_CURL_SHARE,
    ENV_HOUDINI_CURL_VERBOSE,
    ENV_HOUDINI_CURL_IPVERSION,
    ENV_HOUDINI_LIC_ASYNC,
    ENV_HOUDINI_LIC_WEBSOCKET,

    // CHOP
    ENV_HOUDINI_CHOP_OLDNOISE,

    // SHOP
    ENV_HOUDINI_FULL_SHADERSTRING,
    ENV_HOUDINI_TYPED_SHADERSTRING,

    // VOP
    ENV_HOUDINI_RSL_HASHING,

    // SHLF
    ENV_HOUDINI_NO_DEFAULT_SHELF_TOOLS,
    ENV_HOUDINI_SHELF_EXCLUDE_DIRS_PATTERN,

    // Other
    ENV_HOUDINI_CONDENSE_HIP,
    ENV_HOUDINI_UNBUFFERED_STDINOUT,
    ENV_HOUDINI_VERBOSE_ASSET_LICENSING,
    ENV_HOUDINI_NO_ASSET_INSTANTIATION,
    ENV_HOUDINI_ENABLE_HOM_ASSERTS,

    // Backwards Compatability
    ENV_HOUDINI4_COMPATIBILITY,
    ENV_HOUDINI55_COMPATIBILITY,
    ENV_HOUDINI6_COMPATIBILITY,
    ENV_HOUDINI7_COMPATIBILITY,
    ENV_HOUDINI8_COMPATIBILITY,
    ENV_HOUDINI95_COMPATIBILITY,
    ENV_HOUDINI10_COMPATIBILITY,
    ENV_HOUDINI11_COMPATIBILITY,

    ENV_HOUDINI11_PERFMON_COMPATIBILITY,
    ENV_HOUDINI10_VOLUME_COMPATIBILITY,
    ENV_HOUDINI6_FILTER_COMPATIBILITY,
    ENV_HOUDINI13_FILTER_COMPATIBILITY,
    ENV_HOUDINI_MUV_ATTRIB_COMPATIBILITY,
    ENV_HOUDINI_SIMPLIFIED_NODE_NAMES,
    ENV_HOUDINI13_VOLUME_COMPATIBILITY,
    ENV_HOUDINI13_GEO_COMPATIBILITY,
    ENV_HOUDINI14_GEO_COMPATIBILITY,
    ENV_HOUDINI15_PARMDATA_COMPATIBILITY,
    ENV_HOUDINI15_5_GEO_COMPATIBILITY,
    ENV_HOUDINI20_5_PEAK_COMPATIBILITY,

    ENV_HOUDINI_LMINFO_VERBOSE,
    // Have houdini check process fallback to the old deprecated API
    ENV_HSERVER_USE_HTTP,
    ENV_HSERVER_LEGACY_ONLY,
    ENV_HOUDINI_LIC_API_VERSION,

    ENV_HOUDINI_SHOW_CUSTOM_TOOLS,

    // hscript
    ENV_HSCRIPT_NO_HISTORY,
    ENV_HSCRIPT_SAFEQUIT,
    ENV_HSCRIPT_ALLOW_BACKGROUND_RENDER,

    ENV_HOUDINI_OLD_CONST_BEHAVIOUR,

    // This is for "internal use" only.  It turns on features that are not
    // ready for prime-time.
    ENV_HOUDINI_EXPERIMENTAL,

    // Maximum number of files to keep in the backup directory
    ENV_HOUDINI_MAX_BACKUP_FILES,

    ENV_HOUDINI_JITTERY_CAMERA,

    ENV_HOUDINI_ERRORLOG_LEVEL,

    ENV_HOUDINI_MAXTHREADS,

    ENV_HOUDINI_MMB_PAN,
    ENV_HOUDINI_INTERNAL_IGNORE_SIGNALS,

    ENV_HOUDINI_EXTERNAL_HELP_BROWSER,
    ENV_HOUDINI_DISABLE_BACKGROUND_HELP_INDEXING,

    ENV_HOUDINI_CASE_SENSITIVE_FS,

    // Controls the number of complete FBX scenes to
    // keep cached in memory after import. Defaults to 1.
    ENV_HOUDINI_MAX_CACHED_FBX_SCENES,

    // Controls whether to transform the results of evaluating a MotionClip
    // by the intrinsic matrix of the packed primitive.
    ENV_HOUDINI_TRANSFORM_MOTIONCLIP,

    ENV_HOUDINI_NETEXCHANGE_HEARTBEAT,
    ENV_HOUDINI_NETEXCHANGE_MINPACKETSIZE,
    ENV_HOUDINI_NETEXCHANGE_QUICKACK,
    ENV_HOUDINI_DOPVOLUME_NANTEST,

    ENV_HOUDINI_SHOW_OLD_RENDER_PROPERTIES,     // Show all properties
    ENV_HOUDINI_SHOW_OLD_SHOPS,

    // OpenGL
    ENV_HOUDINI_OGL_FIXEDVOXELSIZE,
    ENV_HOUDINI_OGL_VOLUMESHADING,
    ENV_HOUDINI_OGL_DITHER_PDF_TRI,

    // OpenCL
    ENV_HOUDINI_OCL_DEVICENUMBER,
    ENV_HOUDINI_OCL_REPORT_MEMORY_USE,
    ENV_HOUDINI_OCL_REPORT_BUILD_LOGS,
    ENV_HOUDINI_OCL_OGL_INTEROP, // Use CE_Context::shouldUseOCLOGLInterop instead of raw access to this that does additional compatability checks
    ENV_HOUDINI_OCL_CACHE_ENABLE,
    ENV_HOUDINI_OCL_CACHE_SIZE,
    // Can be used to force disable the use of images for advection by the Gas
    // Advect CL 2.0 DOP.
    ENV_HOUDINI_OCL_IMAGE_ADVECTION,
    // Can be used to force use of SwiftShader by the Rasterize Geometry COP.
    ENV_HOUDINI_COP_SWIFTSHADER_RASTERIZE,
    // The rasterizer COP can use interop to copy from vulkan memory to OpenCL
    // memory without leaving the GPU. However, this causes a memory leak on
    // some NVIDIA drivers. This environment variable controls that
    // functionality (0 means no interop, 1 means do it if we can).
    ENV_HOUDINI_COP_RASTERIZE_INTEROP,
    ENV_HOUDINI_COP_RASTERIZE_KEEP_CACHE,
    ENV_HOUDINI_OCL_VDB_UNLOAD,
    ENV_HOUDINI_OCL_ATTRIB_UNLOAD,

    ENV_HOUDINI_SAS_ENABLE,
    ENV_HOUDINI_SAS_COMPILE_ENABLE,
    ENV_HOUDINI_SAS_DISABLE_ASSET_DOWNLOAD,

    ENV_HOUDINI_NO_LEGACY_MENUS,

    // Maximum megabytes in write buffer.
    ENV_HOUDINI_IOBUFFER_SIZE,

    ENV_HOUDINI_INTERNAL_CRASH_ON_NANS,

    ENV_HOUDINI_AUTOCONVERT_IMAGE_FILES,
    ENV_HOUDINI_IMAGE_DISPLAY_OVERRIDE,
    ENV_HOUDINI_ANIMATE_NETWORK_CHANGES,

    ENV_HOUDINI_SOP_DISABLE_CACHENODE,
    ENV_HOUDINI_DOP_MAXCACHE,

    ENV_HOUDINI_OGL_FAST_BONES,

    ENV_HOUDINI_DISTRIBUTEDPROJECTION_DIAGNOSTICS,

    ENV_HOUDINI_USE_HFS_OCL,

    ENV_HOUDINI_DISABLE_AUDIO_SERVER,

    ENV_HOUDINI_CHOP_MOTION_SAMPLES,

    ENV_HOUDINI_SOP_DISABLE_COMPILENODE,

#if defined(SYS_ALLOCATOR_TCMALLOC)
    ENV_HOUDINI_DISABLE_TCMALLOCTEST,
#elif defined(SYS_ALLOCATOR_MIMALLOC)
    ENV_HOUDINI_DISABLE_MIMALLOCTEST,
#else
    ENV_HOUDINI_DISABLE_JEMALLOCTEST,
#endif

    ENV_HOUDINI_ENABLE_3DMOUSE,

    ENV_HOUDINI16_5_DEFORM_COMPATIBILITY,

    // Used to force regular LM checks on Steam builds
    ENV_HOUDINI_IGNORE_STEAM_LICENSING,

    // OptiX
    ENV_HOUDINI_NVIDIA_OPTIX_DEVICENUMBER,

    ENV_HOUDINI_WINDOW_REDRAW_RATE,

    // Package
    ENV_HOUDINI_PACKAGE_VERBOSE,
    ENV_HOUDINI_PACKAGE_SKIP,

    // Viewer state
    ENV_HOUDINI_VIEWER_STATE_VERBOSE,

    ENV_HOUDINI_ERROR_ON_ILLEGAL_NODE_EDITS,

    ENV_HOUDINI_DISABLE_SOP_MEMORY_TRACKING,

    ENV_HOUDINI_LOAD_VERIFICATION,

    // TOP
    ENV_HOUDINI_DISABLE_PDG,
    ENV_HOUDINI_DISABLE_PDG_DATALAYER,
    ENV_HOUDINI_PDG_TYPE_ERROR,
    ENV_HOUDINI_PDG_EXPERIMENTAL,
    ENV_HOUDINI_PDG_CACHE_DEBUG,
    ENV_HOUDINI_PDG_EXPR_DEBUG,
    ENV_HOUDINI_PDG_NODE_DEBUG,
    ENV_HOUDINI_PDG_SCHEDULER_DEBUG,
    ENV_HOUDINI_PDG_SERVICE_DEBUG,
    ENV_HOUDINI_PDG_WORK_ITEM_DEBUG,
    ENV_HOUDINI_PDG_TRANSFER_DEBUG,
    ENV_HOUDINI_PDG_DEFAULT_SERVICE_POOL_SIZE,

    // HAPI
    ENV_HOUDINI_ENGINE_SESSIONSYNC_EXPERIMENTAL,

    // LOP
    ENV_HOUDINI_LOP_PLACEHOLDER_LAYERS,
    ENV_HOUDINI_LOP_STITCH_DEDUPLICATE_SAMPLES,
    ENV_HOUDINI_USD_SAVE_REMOVE_HFS,
    ENV_HOUDINI_USD_STALE_RENDERS,
    ENV_HOUDINI_EDIT_PROPERTIES_STRICT,
    ENV_HOUDINI_SOPIMPORT_XFORMCOMMONAPI,

    ENV_HOUDINI_FAST_TRANSFORM_HANDLES,

    // HDA plugin for USD geometry cache size
    ENV_HOUDINI_HDADYNAMICPAYLOAD_CACHESIZE,

    // Disables loading of individual third-party USD plugins
    ENV_HOUDINI_DISABLE_USDGLTF,
    ENV_HOUDINI_DISABLE_USDFBX,
    ENV_HOUDINI_DISABLE_USDSBSAR,

    ENV_HOUDINI17_COMPATIBILITY,

    ENV_HOUDINI18_COMPATIBILITY,

    ENV_HOUDINI_DISABLE_NESTED_MULTITHREADING,

    // Send python panel erros to the console
    ENV_HOUDINI_CONSOLE_PYTHON_PANEL_ERROR,

    ENV_HOUDINI_VIEWPORT_INFO_MAX_FPS,

    ENV_HOUDINI_DELAYSYNC_HDA,

    ENV_HOUDINI_ASYNCIO,

    // Specify whether or not Houdini GL should use Mtlx materials
    ENV_HOUDINI_GL_USE_MATERIALX,

    // New op viewer, defaults to on.
    ENV_HOUDINIX_NEW_VIEWER_OP_HANDLER,

    ENV_HOUDINI19_5_COMPATIBILITY,

    ENV_HOUDINI_VULKAN_VIEWER,

    ENV_HOUDINI_VULKAN_VIEWER_MULTITHREADING,

    ENV_HOUDINI_INTERCEPT_WITH_SCROLLLOCK,

    ENV_KARMA_DICING_LEGACY,            // Karma legacy dicing behaviour
    ENV_KARMA_VARYING_ARRAY_PRIMVARS,   // Varying length array primvars
    ENV_KARMA_RNG_MODE,
    ENV_KARMA_DCM_COMPATIBILITY,

    // Save HDA internal sections alphabetically (where it makes sens)
    ENV_HOUDINI_NODEDATA_ALPHABETICAL_SAVE,

    ENV_HOUDINI_UI_PARSE_VERBOSE,

    // MV
    ENV_HOUDINI_FFMPEG_VERBOSE,

    ENV_HOUDINI_GROOM_RAYTRACE_PARTINGLINES,

    ENV_HOUDINI_PROTOPATHS_IN_INSTANCE_SELECTIONS,

    // microfacet conductor fresnel to fix glowing issue with rough metals
    ENV_KARMA_CONDUCTOR_FRESNEL_FIX,

    // texturing issues relating to bad derivatives
    ENV_KARMA_POLY_DERIV_FIX,

    ENV_HOUDINI_VDB_FORCE_STREAM_SAVE,

    ENV_HOUDINI_ALLOW_PYTHON_SOP_MULTITHREADING,

    ENV_KARMA_PROTOTYPE_DATA_SHARING,

    ENV_KARMA_LEVELSET_METHOD,

    ENV_HOUDINI_OCL_IGNORE_INTEL_GPU,
    ENV_HOUDINI_OCL_IGNORE_NONDOUBLE_DEVICES,

    // Suppress creation of the non-critical files when expanding an HDA
    ENV_HOUDINI_HDA_SUPPRESS_OPTIONAL_FILES,

    // Tells Houdini to prefer "last cooked" context options over "global"
    //  options when a node is asked to cook with its last cooked options.
    ENV_HOUDINI_NEW_CONTEXT_OPTION_RULES,

    ENV_HOUDINI_INTERNAL_QUICK_EXIT,

    ENV_HOUDINI_ACTIVE_RENDER_DELEGATE_COUNT,

    ENV_HOUDINI_AUTO_DOWNLOAD_SHFS,

    ENV_HOUDINI_DISABLE_OPENFX_DEFAULT_PATH,

    ENV_HOUDINI_CACHE_SEARCH_PATHS_AT_STARTUP,
    ENV_HOUDINI_DONT_PURGE_SEARCH_PATH_CACHE_AFTER_STARTUP,
    ENV_HOUDINI_CACHE_INDEX_FILES_AT_STARTUP,
    ENV_HOUDINI_DONT_PURGE_INDEX_FILE_CACHE_AFTER_STARTUP,

    ENV_HOUDINI_CHECK_FOR_SLOW_FS_DIRECTORY_LISTING,

    ENV_KARMA_OBJ_SPACE_DISPLACEMENT,

    // Change to behavior of primitive sub-patterns. New behavior is
    // definitely more correct, but might change things in unexpected ways.
    ENV_HOUDINI_ALLOW_INSTANCES_IN_SUBPATTERNS,

    ENV_HOUDINI_MEMORY_RELEASE_RATE,

    // APEX: Private Interface
    ENV_HOUDINI_APEX_UNHIDE_NODES,

    ENV_HOUDINI_MINIMAL_SAVE,

    ENV_HOUDINI_BLOSC_COMPRESSION_LEVEL,

    ENV_HOUDINI_UNDO_IDLE_TIMEOUT,

    ENV_KARMA_XPU_GSPLATS_RENDER_MODE,

    ENV_KARMA_ENABLE_VOLUMELIGHT_IN_LIGHTTREE,

    ENV_HOUDINI_STL_SAVE_BINARY,

    // Control whether the Solaris Scene Graph Tree should sort prims
    // alphabetically, or use the USD prim "child order".
    ENV_HOUDINI_SCENEGRAPHTREE_ALPHASORT,

    ENV_HOUDINI_COP_AGGRESSIVE_UNLOAD,

    ENV_HOUDINI_OIIO_FORCE_OCIO,

    ENV_MAX_INT_CONTROLS // <- Must be last
};

enum UT_FltControl
{
    // UT: Public interface
    ENV_HOUDINI_GAUSS_EXP,
    ENV_HOUDINI_MITCHELL_B,
    ENV_HOUDINI_MITCHELL_C,

    // UT: Internal variables
    ENV_HOUDINI_SYSTRACE_THRESH,

    // IMG: Public interface
    ENV_HOUDINI_CINEON_FILM_GAMMA,
    ENV_HOUDINI_IMAGE_DISPLAY_GAMMA,

    // RE
    ENV_HOUDINI_OGL_MAX_GL_VERSION,

    // UI
    ENV_HOUDINI_CHOP_LINE_WIDTH,
    ENV_HOUDINI_COLOR_PICKER_GAMMA,

    // GR
    ENV_HOUDINI_LOD,

    // Custom
    ENV_HOUDINI_WF_GAMMA,

    // ROP: Internal variables
    ENV_HOUDINI_CHECK_XFORM,

    // OpenCL: Memory pool size, as percentage of GPU memory.
    ENV_HOUDINI_OCL_MEMORY_POOL_SIZE,

    // OpenCL: amount of VRAM that IMX layers are allowed to use.
    ENV_HOUDINI_OCL_COP_MEMORY,

    // CH
    ENV_HOUDINI_FPS,

    // LOP interactive selection redraw time
    ENV_HOUDINI_MAX_SELECTION_REDRAW_TIME,

    // Percent grey that shows as a zero exposure value when displaying
    // pixel luminance in log terms. Values outside (0, 1) cause us to
    // not calculate or display luminance in log terms.
    ENV_HOUDINI_ZERO_EXPOSURE,

    ENV_MAX_FLT_CONTROLS // <- Must be last
};

enum UT_StrControl
{
    // UT: Public interface
    ENV_HOME,
    ENV_USER,
    ENV_EDITOR,
    ENV_VISUAL,
    ENV_SHELL,
    ENV_HFS,
    ENV_SHFS,
    ENV_HOUDINI_OS,
    ENV_HOUDINI_TEMP_DIR,
    ENV_HOUDINI_DESKTOP_DIR,
    ENV_HOUDINI_UNDO_DIR,
    ENV_HOUDINI_MESSAGE_CMD,
    ENV_HOUDINI_CONFIRM_CMD,
    ENV_HOUDINI_ASSERT_CMD,
    ENV_HOUDINI_WEB_BROWSER_CMD,
    ENV_HOUDINI_TERMINAL_CMD,
    ENV_HOUDINI_CONDENSE_BLOCKLIST,
    ENV_HOUDINI_CONSOLE_FLAGS,
    ENV_HOUDINI_BEARER_TOKENS,

    // UT: Internal variables
    ENV_HOUDINI_SYSTRACE_FILENAME,
    ENV_HOUDINI_PATHMAP,
    ENV_SIDEFX_WEBSITE,

    // external tools
    ENV_HOUDINI_COMPARE,

    // IMG: Public interface
    ENV_HOUDINI_DEF_TEXTURE_COLOR,
    ENV_HOUDINI_TEXTURE_DISK_CACHE,

    // VEX(VMAT)
    ENV_HOUDINI_DEFAULT_SURFACE,
    ENV_HOUDINI_DEFAULT_VOLUME,
    ENV_HOUDINI_DEFAULT_LIGHT,
    ENV_HOUDINI_DEFAULT_LIGHTSURFACE,
    ENV_HOUDINI_DEFAULT_AMBIENT,
    ENV_HOUDINI_DEFAULT_MATTE,
    ENV_HOUDINI_DEFAULT_SHADOW,
    ENV_HOUDINI_VEX_JIT_OPTIMIZE,

    // HOM
    ENV_HOUDINI_SCRIPT_LICENSE,

    // OP
    ENV_HOUDINI_HIP_DEFAULT_NAME,       // "untitled.hip"
    ENV_HOUDINI_COPY_SUFFIX,
    ENV_HOUDINI_OPNAMESPACE_HIERARCHY,

    // VOP
    ENV_HOUDINI_VOP_DEFINITIONS_PATH,

    // GEO
    ENV_HOUDINI_RMAN_CURVE_BASIS,

    // COP
    ENV_HOUDINI_CINEON_RENDER_LUT,
    ENV_HOUDINI_CINEON_PREVIEW_LUT,
    ENV_HOUDINI_COP_DISKDEFAULT,
    ENV_HOUDINI_IMAGE_DISPLAY_LUT,
    ENV_HOUDINI_IMAGE_INSPECT_LUT,
    ENV_HOUDINI_OCIO_SRGB_FILE_COLORSPACE,

    // CHOP
    ENV_HOUDINI_UNITS,

    // TOP
    ENV_HOUDINI_PDG_TYPE_SKIPLIST,
    
    // LOP
    ENV_HOUDINI_DEFAULT_DOMELIGHT_TEXTURE,

    // IFD
    ENV_HOUDINI_RI_SHADERPATH,
    ENV_HOUDINI_RI_RIXPLUGINPATH,
    ENV_HOUDINI_RI_TEXTUREPATH,
    ENV_HOUDINI_RI_EYESPLITS,
    ENV_MANTRA_ENGINE_PROCEDURAL,

    // UI
    ENV_HOUDINI_FILE_VIEWER,
    ENV_HOUDINI_UI_PATH,
    ENV_HOUDINI_UI_RESOURCES,
    ENV_HOUDINI_UI_APP_PATH,
    ENV_HOUDINI_UI_AUDIO_PATH,
    ENV_HOUDINI_UI_CURSOR_PATH,
    ENV_HOUDINI_UI_DIALOG_PATH,
    ENV_HOUDINI_UI_ICON_PATH,
    ENV_HOUDINI_UI_TEMPLATE_PATH,
    ENV_HOUDINI_ICON_CACHE_DIR,

    // FUI
    ENV_HOUDINI_STPATH,
    ENV_HOUDINI_STEDIT,

    // CHUI
    ENV_HOUDINI_CHOP_IMAGE,

    // OPUI
    ENV_HOUDINI_DOUBLEBUFFER,
    ENV_HOUDINI_WORKSHEET_BOXPICK,
    ENV_HOUDINI_DEFOPTYPEPREFIX,

    // VEX(VCC)
    ENV_HOUDINI_VEX_COMPILER,

    // Custom
    ENV_HOUDINI_ABEKAS_LOGIN_NAME,
    ENV_HOUDINI_ABEKAS_LOGIN_PASS,
    ENV_HOUDINI_MPLAY_WRITE_CMD,
    ENV_HOUDINI_MPLAY_FLIP_CMD,
    ENV_HOUDINI_MPLAY_LOCKPATH,
    ENV_HOUDINI_PLAY_WRITE_CMD,
    ENV_HOUDINI_PLAY_FLIP_CMD,
    ENV_HOUDINI_VIEW_METACAM,   //OTLs that lock to view in a special way

    // Path variables
    ENV_HOUDINI_PATH,
    ENV_HOUDINI_SHFS_PATH,

    ENV_HOUDINI_DSO_PATH,
    ENV_HOUDINI_IMAGE_DSO_PATH,
    ENV_HOUDINI_AUDIO_DSO_PATH,
    ENV_HOUDINI_PDG_DSO_PATH,
    ENV_HOUDINI_PDGD_DSO_PATH,
    ENV_HOUDINI_VEX_DSO_PATH,
    ENV_HOUDINI_OPUI_DSO_PATH,
    ENV_HOUDINI_USD_DSO_PATH,
    ENV_HOUDINI_MOCAPSTREAM_DSO_PATH,
    ENV_HOUDINI_MV_DSO_PATH,
    ENV_MANTRA_DSO_PATH,
    ENV_KARMA_DSO_PATH,
    ENV_HOUDINI_OTL_PATH,
    ENV_HOUDINI_OPLIBRARIES_PATH,
    ENV_HOUDINI_OTLSCAN_PATH,
    ENV_HOUDINI_SCRIPT_PATH,
    ENV_HOUDINI_SOHO_PATH,
    ENV_HOUDINI_GALLERY_PATH,
    ENV_HOUDINI_PARM_DS_PATH,
    ENV_HOUDINI_DESKTOP_PATH,
    ENV_HOUDINI_ASSET_STORE_PATH,
    ENV_HOUDINI_TOOLBAR_PATH,
    ENV_HOUDINI_RADIALMENU_PATH,
    ENV_HOUDINI_RAMP_PATH,
    ENV_HOUDINI_LUT_PATH,
    ENV_HOUDINI_CUSTOM_PATH,
    ENV_HOUDINI_PYTHON_PANEL_PATH,
    ENV_HOUDINI_MENU_PATH,
    ENV_HOUDINI_PDG_PATH,
    ENV_HOUDINI_PDGD_PATH,

    ENV_HOUDINI_TEXTURE_PATH,
    ENV_HOUDINI_GEOMETRY_PATH,
    ENV_HOUDINI_CLIP_PATH,

    ENV_HOUDINI_VEX_PATH,

    ENV_HOUDINI_GLSL_PATH,
    ENV_HOUDINI_SPIRV_PATH,

    ENV_HOUDINI_OUTLINEFONT_PATH,

    ENV_HOUDINI_VIEWERSTATE_PATH,
    ENV_HOUDINI_VIEWERHANDLE_PATH,
    ENV_HOUDINI_HUSDPLUGINS_PATH,
    ENV_HOUDINI_LAYOUTPLUGINS_PATH,
    ENV_HOUDINI_CLONEPLUGINS_PATH,

    ENV_HOUDINI_LAUNCHER_PATH,

    ENV_HOUDINI_BACKUP_DIR,

    ENV_HOUDINI_BACKUP_FILENAME,
    ENV_HOUDINI_AUTOSAVE_FILENAME,
    ENV_HOUDINI_STASH_DIR,
    ENV_HOUDINI_STASH_FILENAME,

    ENV_HOUDINI_VIEW_MANTRA,
    ENV_HOUDINI_VIEW_RMAN,
    ENV_HOUDINI_DEFAULT_RENDERERS,
    ENV_HOUDINI_DEFAULT_RIB_RENDERER,
    ENV_HOUDINI_RIBSHADER_DIR,
    ENV_HOUDINI_RIBTEMP_DIR,

    ENV_HOUDINI_HUSK_DEFAULT_HEADLIGHT,
    ENV_HOUDINI_HUSK_DEFAULT_DELEGATE,

    ENV_KARMA_XPU_DEVICES,

    ENV_HOUDINI_THUMB_RENDER,

    // These are here so we can have them show up in hconfig and provide
    // help.  They should only be used implicitly.
    ENV_HSITE,          // Between HFS and HOME.
    ENV_JOB,            // We should not use JOB!

    ENV_HOUDINI_ERRORLOG_FILENAME,

    ENV_HOUDINI_SPLASH_MESSAGE,
    ENV_HOUDINI_SPLASH_MESSAGE_FONT,
    ENV_HOUDINI_SPLASH_MESSAGE_FONT_SIZE,
    ENV_HOUDINI_SPLASH_MESSAGE_COLOR,
    ENV_HOUDINI_SPLASH_FILE,

    ENV_HOUDINI_GEOMETRY_FORMAT,

    // OPENGL
    ENV_HOUDINI_OGL_DEBUG_EXCLUDE,
    ENV_HOUDINI_OGL_PICKBUFFER_PATH,
    ENV_HOUDINI_OGL_SNAPBUFFER_PATH,
    ENV_HOUDINI_OGL_BEAUTY_PATH,
    ENV_HOUDINI_OGL_VIEWPORT_PATH,
    ENV_HOUDINI_OGL_DITHER_TEXTURE,

    // OPENCL
    ENV_HOUDINI_OCL_DEVICETYPE,
    ENV_HOUDINI_OCL_VENDOR,
    ENV_HOUDINI_OCL_PATH,
    ENV_HOUDINI_OCL_FEATURE_DISABLE,
    ENV_HOUDINI_OCL_KERNEL_OPTIONS,
    ENV_HOUDINI_OCL_CACHE_DIR,

    // Orbolt
    ENV_HOUDINI_SAS_SERVER,

    // Anonymous Usage Statistics
    ENV_HOUDINI_STATS_API_URL,

    ENV_HOUDINI_DSO_EXCLUDE_PATTERN,

    ENV_HOUDINI_USER_PREF_DIR,

    ENV_HOUDINI_AUTHOR,

    // Optix
    ENV_HOUDINI_NVIDIA_OPTIX_DSO_PATH,

    ENV_HOUDINI_PACKAGE_DIR,

    // BGEO plugin for USD default load arguments
    ENV_HOUDINI_BGEO_TO_USD_DEFAULT_ARGS,

    // LM
    ENV_HOUDINI_API_KEY_FILE,
    ENV_HOUDINI_LIC_OPT,
    ENV_HOUDINI_CORE_LIC_OPT,
    ENV_HOUDINI_FX_LIC_OPT,
    ENV_HOUDINI_INDIE_LIC_OPT,
    ENV_HOUDINI_NC_LIC_OPT,
    ENV_HOUDINI_EXPER_LIC_OPT,
    ENV_HOUDINI_PDG_LIC_OPT,
    ENV_HOUDINI_HYTHON_LIC_OPT,
    ENV_HOUDINI_MANTRA_LIC_OPT,
    ENV_HOUDINI_KARMA_LIC_OPT,
    ENV_HOUDINI_MPLAY_LIC_OPT,
    ENV_HOUDINI_PLUGIN_LIC_OPT,
    ENV_HOUDINI_UNREAL_PLUGIN_LIC_OPT,
    ENV_HOUDINI_UNITY_PLUGIN_LIC_OPT,
    ENV_HOUDINI_EDUCATION_LIC_OPT,
    ENV_HOUDINI_OVERRIDE_LIC_VERSION,
    ENV_HOUDINI_LICENSE_DIR,

    // Python
    ENV_HOUDINI_PYTHONWARNINGS,

    // Logging
    ENV_HOUDINI_DEFAULT_LOG_SOURCES,
    ENV_HOUDINI_DEFAULT_LOG_FILE,
    ENV_HOUDINI_DEFAULT_LOG_FILE_SOURCES,

    // Default asset/material catalog databases
    ENV_HOUDINI_ASSETCATALOG_DB_FILE,
    ENV_HOUDINI_MATERIALCATALOG_DB_FILE,
    ENV_HOUDINI_ANIMATIONCATALOG_FILE,

    // Networking
    ENV_HOUDINI_HTTP_NOPROXY,
    ENV_HOUDINI_HTTP_PROXY,

    // HQueue
    ENV_HOUDINI_HQUEUE_SERVER,
    ENV_HOUDINI_HQUEUE_HFS,
    ENV_HOUDINI_HQUEUE_HFS_LINUX,
    ENV_HOUDINI_HQUEUE_HFS_MACOS,
    ENV_HOUDINI_HQUEUE_HFS_WINDOWS,

    // Render delegate to use by default on new Houdini clones
    ENV_HOUDINI_DEFAULT_ROP_RENDER_DELEGATE,
    ENV_HOUDINI_DEFAULT_CLONE_RENDER_DELEGATE,
    ENV_HOUDINI_DEFAULT_SCENEVIEWER_RENDER_DELEGATE,
    ENV_HOUDINI_FORCE_SCENEVIEWER_RENDER_DELEGATE,

    // Render Product Types that should not show their AOVs in the list
    // that shows up in the viewport menu.
    ENV_HOUDINI_HIDE_PRODUCT_TYPES,

    ENV_HOUDINI_CUSTOM_RECIPE_DIR,
    ENV_HOUDINI_CUSTOM_RECIPE_LIBRARY,

    ENV_HOUDINI_HELP_BROWSER_TRUSTED_URLS,

    // When a loaded HDA changes on disk, perform this action by default
    // instead of showing the interactive message.
    ENV_HOUDINI_HDA_CHANGED_ON_DISK_DEFAULT_ACTION,

    // Compression method to specify a default compression method for
    // .hip files
    ENV_HOUDINI_HIPFILE_COMPRESSION,

    // Compression codec to use when compressing in blosc.
    ENV_HOUDINI_BLOSC_COMPRESSION_CODEC,

    ENV_HOUDINI_PACKAGE_SKIPLIST,

    ENV_MAX_STR_CONTROLS // <- Must be last
};

// If these constraints are ever violated in a HEAD branch, it's time to
// increase MAX_CONTROLS_WITH_BUFFER. If these constraints are violated in
// a released build, get rid of the "+50" part, and if they are exceeded
// again then we must increate MAX_CONTROLS_WITH_BUFFER in a daily build and
// break ABI compatiblity. But hopefully that won't happen...
SYS_STATIC_ASSERT(ENV_MAX_INT_CONTROLS + 50 < MAX_CONTROLS_WITH_BUFFER);
SYS_STATIC_ASSERT(ENV_MAX_FLT_CONTROLS + 50 < MAX_CONTROLS_WITH_BUFFER);
SYS_STATIC_ASSERT(ENV_MAX_STR_CONTROLS + 50 < MAX_CONTROLS_WITH_BUFFER);

class UT_API UT_EnvControl
{
public:
     UT_EnvControl();
    ~UT_EnvControl();

    UT_EnvControl(const UT_EnvControl &) = delete;
    UT_EnvControl &operator=(const UT_EnvControl &) = delete;

    void init();

    static int           getInt(UT_IntControl i)
                                { return getControl().myIValues[i]; }
    static fpreal        getFloat(UT_FltControl i)
                                { return getControl().myFValues[i]; }
    static const char   *getString(UT_StrControl i)
                                { return getControl().mySValues[i]; }

    // Look up the appropriate variable name for the token
    static const char   *getIntVar(UT_IntControl i);
    static const char   *getFloatVar(UT_FltControl i);
    static const char   *getStringVar(UT_StrControl i);

    static void          setStringVar(UT_StrControl i, const char *value);

    // Look up the appropriate old style variable name for the token.  This can
    // be used to check for old environment variables.
    static const char   *getOldIntVar(UT_IntControl i);
    static const char   *getOldFloatVar(UT_FltControl i);
    static const char   *getOldStringVar(UT_StrControl i);

    /// Indicate that the given variable changed and update our cached values.
    /// If varname is NULL, then all variables are updated.
    static void          varChanged(const char *varname)
                            { varChanged(varname, nullptr); }

    /// Update the cached varname value with the given value so that we can
    /// avoid an extraneous HoudiniGetenv() for the equivalent code snippet:
    /// @code
    ///      HoudiniSetenv(name, value);
    ///      UT_EnvControl::varChanged(name);
    /// @endcode
    /// @return true if name was found and value is non-null, in which case the
    /// HoudiniSetenv() was called, else false is returned.
    static bool          varChanged(const char *varname, const char *value);

    static void          changeExistLookupDefault(UT_IntControl i, int new_def);

    /// Queries the cached variable value.  Unrecognized variables are
    /// returned as UT_Variant::Type::Unknown.  String values are returned
    /// as UT_Variant::Type::Pointer to allow distinguishing between null
    /// pointers and empty strings.  If you intend to hold onto the string
    /// value beyond immediately using it, you must make your own copy!
    static UT_Variant    getVarValue(const char *varname);

    /// Set all additional .env files to be parsed for env variable values.
    /// It is best to call getAdditionalEnvironmentFiles() first and then
    /// append to the list because this function will overwrite all the
    /// additional paths that were previously set.
    /// You can still use the HOUDINI_NO_ENV_FILE_OVERRIDES to disallow
    /// overwrites, knowing that these files get applied AFTER the default
    /// houdini.env file in the user's home directory.
    /// That said, HOUDINI_NO_ENV_FILE will have no effect on this function.
    /// If additional files are set, they will be used, regardless of the
    /// value of HOUDINI_NO_ENV_FILE.
    static void          setAdditionalEnvironmentFiles(
                                        const UT_StringArray &files);

    /// Return the current list of additional environment files.
    static const UT_StringArray&
                         getAdditionalEnvironmentFiles();

    // Print messages collected during init phase to console
    static void logMessages()
    {
        getControl().logMessagesToConsole();
    }

    // Package loader management
    // Load the pakages located in the folders specified by pkg_paths.
    // Use this method for loading package dynamically
    static void loadPackages(UT_StringArray const &pkg_paths, UT_Package::Loader& pkg_loader);
    static UT_Package::Package & loadPackage(char const * pkg_filepath, UT_Package::Loader& pkg_loader);

    // Returns the main package loader, this loader contains all 
    // packages loaded at runtime.
    static UT_Package::Loader& packageLoader();

private:
    void                 doInit(bool init_defaults);
    void                 setDefaults();
    bool                 loadEnvironmentFile(const char *path,
                                             bool allow_overrides);
    void                 loadDefaultEnvironmentFile();
    void                 loadEnvironmentFiles();
    void                 loadEnvironment(bool init_defaults);

    void                 updateExistLookup(int i, const char *value = nullptr);
    void                 updateIntLookup(int i, const char *value = nullptr);
    void                 updateFltLookup(int i, const char *value = nullptr);
    void                 updateStrLookup(int i, bool fix_path,
                                         const char *value = nullptr);

    void                 updateVarTables(UT_Package::Loader const& pkg_loader);

    void                 loadPackageConfig();
    void                 logMessagesToConsole() const;

    int                          myIValues[MAX_CONTROLS_WITH_BUFFER];
    float                        myFValues[MAX_CONTROLS_WITH_BUFFER];
    char                        *mySValues[MAX_CONTROLS_WITH_BUFFER];

    static UT_EnvControl        &getControl()
                                 {
                                    if (!theControl)
                                    {
                                        theControl = new UT_EnvControl();
                                        theControl->init();

                                    }
                                    return *theControl;
                                 }
    static UT_EnvControl        *theControl;

    UT_StringHolder              myLogMessages;
};

#endif