Internal CRT globals and functions

The C runtime (CRT) library contains functions and global variables that are used only to support the public library interface. Some of them are exposed in public headers as implementation details. Although these functions and global variables are accessible through public exports, they're not intended for use by your code. We recommend that you change any code that uses these functions and variables to use public library equivalents instead. These functions may change from version to version. They're listed here to help you identify them. Links are provided when other documentation exists, but in general, these implementation details aren't documented.

Internal CRT globals and value macros

These global variables and macro definitions are used to implement the CRT.

Name
__badioinfo
_acmdln
_commode
_crtAssertBusy
_crtBreakAlloc
__initenv
__lconv
__mb_cur_max
__pioinfo
__unguarded_readlc_active
_wcmdln
__winitenv

Internal CRT functions and function macros

These functions and function macros are used to implement the CRT and the C++ Standard Library.

Name
__acrt_iob_func
__AdjustPointer
__BuildCatchObject
__BuildCatchObjectHelper
__C_specific_handler
_calloc_base
_chkesp
__chkstk
_chkstk
_chvalidator
_chvalidator_l
_CIacos
_CIasin
_CIatan
_CIatan2
_CIcos
_CIcosh
_CIexp
_CIfmod
_CIlog
_CIlog10
_CIpow
_CIsin
_CIsinh
_CIsqrt
_CItan
_CItanh
__clean_type_info_names_internal
_configure_narrow_argv
_configure_wide_argv
__conio_common_vcprintf
__conio_common_vcprintf_p
__conio_common_vcprintf_s
__conio_common_vcscanf
__conio_common_vcwprintf
__conio_common_vcwprintf_p
__conio_common_vcwprintf_s
__conio_common_vcwscanf
__CppXcptFilter
__create_locale
_crt_atexit
_crt_at_quick_exit
__crtCompareStringA
__crtCompareStringEx
__crtCompareStringW
__crtCreateEventExW
__crtCreateSemaphoreExW
__crtCreateSymbolicLinkW
_crt_debugger_hook
__crtEnumSystemLocalesEx
__crtFlsAlloc
__crtFlsFree
__crtFlsGetValue
__crtFlsSetValue
_CrtGetCheckCount
__crtGetDateFormatEx
__crtGetFileInformationByHandleEx
__crtGetLocaleInfoEx
__crtGetShowWindowMode
__crtGetTickCount64
__crtGetTimeFormatEx
__crtGetUserDefaultLocaleName
__crtInitializeCriticalSectionEx
__crtIsPackagedApp
__crtIsValidLocaleName
__crtLCMapStringA
__crtLCMapStringEx
__crtLCMapStringW
_CrtSetCheckCount
_CrtSetDbgBlockType
__crtSetFileInformationByHandle
__crtSetThreadStackGuarantee
__crtSetUnhandledExceptionFilter
__crtSleep
__crtTerminateProcess
__crtUnhandledException
__CxxDetectRethrow
__CxxExceptionFilter
__CxxFrameHandler
__CxxFrameHandler2
__CxxFrameHandler3
__CxxLongjmpUnwind
__CxxQueryExceptionSize
__CxxRegisterExceptionObject
_CxxThrowException
__CxxUnregisterExceptionObject
_dclass
__DestructExceptionObject
__dllonexit
__doserrno
_dosmaperr
_dpcomp
_dsign
__dstbias
_dtest
_EH_prolog
_errno
_except_handler
_except_handler2
_except_handler3
_except_handler4_common
_except1
_execute_onexit_table
_fdclass
_fdpcomp
_fdsign
_fdtest
_filbuf
_FindAndUnlinkFrame
_flsbuf
__fpe_flt_rounds
_FPE_Raise
__fpecode
__FrameUnwindFilter
_fread_nolock_s
_free_base
__free_locale
_freea_s
_freefls
_ftol
__get_current_locale
__get_flsindex
_get_initial_narrow_environment
_get_initial_wide_environment
_get_narrow_winmain_command_line
_get_stream_buffer_pointers
__get_tlsindex
_get_wide_winmain_command_line
_Getdays
__getmainargs
_Getmonths
__GetPlatformExceptionInfo
_getptd
_Gettnames
_global_unwind2
_inconsistency
_initialize_lconv_for_unsigned_char
_initialize_narrow_environment
_initialize_onexit_table
_initialize_wide_environment
_initptd
_invalid_parameter
_invoke_watson
__iob_func
_IsExceptionObjectToBeDestroyed
___lc_codepage_func
___lc_collate_cp_func
___lc_locale_name_func
__lconv_init
_ldclass
_ldpcomp
_ldsign
_ldtest
__libm_sse2_acos
_libm_sse2_acos_precise
__libm_sse2_acosf
__libm_sse2_asin
_libm_sse2_asin_precise
__libm_sse2_asinf
__libm_sse2_atan
_libm_sse2_atan_precise
__libm_sse2_atan2
__libm_sse2_atanf
__libm_sse2_cos
_libm_sse2_cos_precise
__libm_sse2_cosf
__libm_sse2_exp
_libm_sse2_exp_precise
__libm_sse2_expf
__libm_sse2_log
_libm_sse2_log_precise
__libm_sse2_log10
_libm_sse2_log10_precise
__libm_sse2_log10f
__libm_sse2_logf
__libm_sse2_pow
_libm_sse2_pow_precise
__libm_sse2_powf
__libm_sse2_sin
_libm_sse2_sin_precise
__libm_sse2_sinf
_libm_sse2_sqrt_precise
__libm_sse2_tan
_libm_sse2_tan_precise
__libm_sse2_tanf
_local_unwind2
_local_unwind4
_lock_locales
_longjmpex
_malloc_base
___mb_cur_max_func
___mb_cur_max_l_func
_mbctype
_NLG_Dispatch2
_NLG_Return
_NLG_Return2
__p___argc
__p___argv
__p___initenv
__p___mb_cur_max
__p___wargv
__p___winitenv
__p__acmdln
__p__commode
__p__crtAssertBusy
__p__crtBreakAlloc
__p__crtDbgFlag
__p__daylight
__p__dstbias
__p__environ
__p__fmode
__p__iob
__p__mbcasemap
__p__mbctype
__p__pctype
__p__pgmptr
__p__pwctype
__p__timezone
__p__tzname
__p__wcmdln
__p__wenviron
__p__wpgmptr
_pctype
__pctype_func
_pwctype
__pwctype_func
__pxcptinfoptrs
_query_app_type
_realloc_base
_register_onexit_function
_register_thread_local_exe_atexit_callback
__report_gsfailure
__RTCastToVoid
__RTDynamicCast
__RTtypeid
_seh_filter_dll
_seh_filter_exe
_seh_longjmp_unwind
_seh_longjmp_unwind4
__set_app_type
_set_malloc_crt_max_wait
_setjmp3
__setlc_active
___setlc_active_func
__setusermatherr
_SetWinRTOutOfMemoryExceptionCallback
_sopen_dispatch
__std_exception_copy
__std_exception_destroy
__std_type_info_destroy_list
__std_type_info_name
__stdio_common_vfprintf
__stdio_common_vfprintf_p
__stdio_common_vfprintf_s
__stdio_common_vfscanf
__stdio_common_vfwprintf
__stdio_common_vfwprintf_p
__stdio_common_vfwprintf_s
__stdio_common_vfwscanf
__stdio_common_vsnprintf_s
__stdio_common_vsnwprintf_s
__stdio_common_vsprintf
__stdio_common_vsprintf_p
__stdio_common_vsprintf_s
__stdio_common_vsscanf
__stdio_common_vswprintf
__stdio_common_vswprintf_p
__stdio_common_vswprintf_s
__stdio_common_vswscanf
_Strftime
__STRINGTOLD
__STRINGTOLD_L
__strncnt
__sys_errlist
__sys_nerr
__threadhandle
__threadid
__timezone
__TypeMatch
__tzname
__unDName
__unDNameEx
__unDNameHelper
__unguarded_readlc_active
___unguarded_readlc_active_add_func
_unloaddll
_unlock_locales
_vacopy
_ValidateExecute
_ValidateRead
_ValidateWrite
_VCrtDbgReportA
_VCrtDbgReportW
_W_Getdays
_W_Getmonths
_W_Getnames
_W_Gettnames
_Wcsftime
__wcsncnt
__wgetmainargs
_wsopen_dispatch
_Xbad_alloc
_Xlength_error

See also

Universal C runtime routines by category