Standard Types
The Microsoft run-time library defines the following standard types.
| Type | Description | Declared In |
| clock_t structure | Stores time values; used by clock. | TIME.H |
| _complex structure | Stores real and imaginary parts of complex numbers; used by _cabs. | MATH.H |
| _dev_t short or unsigned integer | Represents device handles. | SYS\TYPES.H |
| div_t, ldiv_t structures | Store values returned by div and ldiv, respectively. | STDLIB.H |
| _exception structure | Stores error information for _matherr. | MATH.H |
| FILE structure | Stores information about current state of stream; used in all stream I/O operations. | STDIO.H |
| _finddata_t, _wfinddata_t, _wfinddatai64_t structures | _finddata_t stores file-attribute information returned by _findfirst and_findnext. _wfinddata_t stores file-attribute information returned by _wfindfirst and _wfindnext. _wfinddatai64_t stores file-attribute information returned by _wfindfirsti64 and _wfindnexti64. | _finddata_t: IO.H _wfinddata_t: IO.H, WCHAR.H _wfinddatai64_t: IO.H, WCHAR.H |
| _FPIEEE_RECORD structure | Contains information pertaining to IEEE floating-point exception; passed to user-defined trap handler by _fpieee_flt. | FPIEEE.H |
| fpos_t (long integer, __int64, or structure, depending on the target platform) |
Used by fgetpos and fsetpos to record information for uniquely specifying every position within a file. | STDIO.H |
| _HEAPINFO structure | Contains information about next heap entry for _heapwalk. | MALLOC.H |
| jmp_buf array | Used by setjmp and longjmp to save and restore program environment. | SETJMP.H |
| lconv structure | Contains formatting rules for numeric values in different countries. | LOCALE.H |
| _off_t long integer | Represents file-offset value. | SYS\TYPES.H |
| _onexit_t pointer | Returned by _onexit. | STDLIB.H |
| _PNH pointer to function | Type of argument to _set_new_handler. | NEW.H |
| ptrdiff_t integer | Result of subtraction of two pointers. | STDDEF.H |
| sig_atomic_t integer | Type of object that can be modified as atomic entity, even in presence of asynchronous interrupts; used with signal. | SIGNAL.H |
| size_t unsigned integer | Result of sizeof operator. | STDDEF.H and other include files |
| _stat structure | Contains file-status information returned by _stat and _fstat. | SYS\STAT.H |
| time_t long integer | Represents time values in mktime and time. | TIME.H |
| _timeb structure | Used by _ftime to store current system time. | SYS\TIMEB.H |
| tm structure | Used by asctime, gmtime, localtime, mktime, and strftime to store and retrieve time information. | TIME.H |
| _utimbuf structure | Stores file access and modification times used by _utime to change file-modification dates. | SYS\UTIME.H |
| va_list structure | Used to hold information needed by va_arg and va_end macros. Called function declares variable of type va_list that can be passed as argument to another function. | STDARG.H |
| wchar_t internal type of a wide character | Useful for writing portable programs for international markets. | STDDEF.H, STDLIB.H |
| wctrans_t integer | Represents locale-specific character mappings. | WCTYPE.H |
| wctype_t integer | Can represent all characters of any national character set. | WCHAR.H |
| wint_t integer | Type of data object that can hold any wide character or wide end-of-file value. | WCHAR.H |