Global Variables

The Microsoft C run-time library provides the following global variables or macros. Several of these global variables or macros have been deprecated in favor of more-secure functional versions, which we recommend you use instead of the global variables.

Variable	Description
__argc, __argv, __wargv	Contains the command-line arguments.
_daylight, _dstbias, _timezone, and _tzname	Deprecated. Instead, use _get_daylight, _get_dstbias, _get_timezone, and _get_tzname. Adjusts for local time; used in some date and time functions.
errno, _doserrno, _sys_errlist, and _sys_nerr	Deprecated. Instead, use _get_errno, _set_errno, _get_doserrno, _set_doserrno, perror and strerror. Stores error codes and related information.
_environ, _wenviron	Deprecated. Instead, use getenv_s, _wgetenv_s, _dupenv_s, _wdupenv_s, _putenv_s, and _wputenv_s. Pointers to arrays of pointers to the process environment strings; initialized at startup.
_fmode	Deprecated. Instead, use _get_fmode or _set_fmode. Sets default file-translation mode.
_iob	Array of I/O control structures for the console, files, and devices.
_pctype, _pwctype, _wctype, _mbctype, _mbcasemap	Contains information used by the character-classification functions.
_pgmptr, _wpgmptr	Deprecated. Instead, use _get_pgmptr or _get_wpgmptr. Initialized at program startup to the fully-qualified or relative path of the program, the full program name, or the program name without its file name extension, depending on how the program was invoked.

See Also

Reference

Global Constants

__argc, __argv, __wargv

_get_daylight

_get_dstbias

_get_timezone

_get_tzname

perror

strerror

_get_doserrno

_set_doserrno

_get_errno

_set_errno

_dupenv_s, _wdupenv_s

getenv, _wgetenv

getenv_s, _wgetenv_s

_putenv, _wputenv

_putenv_s, _wputenv_s

_get_fmode

_set_fmode

Other Resources

C Run-Time Library Reference