Win32 Equivalents for C Run-Time Functions

Win32 Equivalents for C Run-Time Functions

The information in this article applies to:

Microsoft Win32 Application Programming Interface (API), included with:

Operating system: Microsoft Windows NT, versions 3.1 , 3.5 , 3.51,4.0,2k
Microsoft Windows 95

SUMMARY

Many of the C Run-time functions have direct equivalents in the Win32 application programming interface (API). This article lists the C Run-time functions by category with their Win32 equivalents or the word "none" if no equivalent exists.

MORE INFORMATION

NOTE: the functions that are followed by an asterisk (*) are part of the 16-bit C Run-time only. Functions that are unique to the 32-bit C Run-time are listed separately in the last section. All other functions are common to both C Run-times.

Buffer Manipulation

C Run time	Win32 Equivalent
_memccpy	none
memchr	none
memcmp	none
memcpy	CopyMemory (See Note 6)
_memicmp	none
memmove	MoveMemory (See Note 6)
memset	FillMemory, ZeroMemory (See Note 6)
_swab	None

Character Classification

C Run time	Win32 Equivalent
Isalnum	IsCharAlphaNumeric
Isalpha	IsCharAlpha, GetStringTypeW (Unicode)
__isascii	None
iscntrl	None, GetStringTypeW (Unicode)
__iscsym	None
__iscsymf	None
isdigit	None, GetStringTypeW (Unicode)
isgraph	None
islower	IsCharLower, GetStringTypeW (Unicode)
isprint	None
ispunct	None, GetStringTypeW (Unicode)
isspace	None, GetStringTypeW (Unicode)
isupper	IsCharUpper, GetStringTypeW (Unicode)
isxdigit	None, GetStringTypeW (Unicode)
__toascii	None
tolower	CharLower
_tolower	None
toupper	CharUpper
_toupper	None

Directory Control

C Run time	Win32 Equivalent
_chdir	SetCurrentDirectory
_chdrive	SetCurrentDirectory
_getcwd	GetCurrentDirectory
_getdrive	GetCurrentDirectory
_mkdir	CreateDirectory
_rmdir	RemoveDirectory
_searchenv	SearchPath

File Handling

C Run time	Win32 Equivalent
_access	none
_chmod	SetFileAttributes
_chsize	SetEndOfFile
_filelength	GetFileSize
_fstat	See Note 5
_fullpath	GetFullPathName
_get_osfhandle	none
_isatty	GetFileType
_locking	LockFileEx
_makepath	none
_mktemp	GetTempFileName
_open_osfhandle	None
remove	DeleteFile
rename	MoveFile
_setmode	None
_splitpath	None
_stat	None
_umask	None
_unlink	DeleteFile

Creating Text Output Routines

C Run time	Win32 Equivalent
_displaycursor*	SetConsoleCursorInfo
_gettextcolor*	GetConsoleScreenBufferInfo
_gettextcursor*	GetConsoleCursorInfo
_gettextposition*	GetConsoleScreenBufferInfo
_gettextwindow*	GetConsoleWindowInfo
_outtext*	WriteConsole
_scrolltextwindow*	ScrollConsoleScreenBuffer
_settextcolor*	SetConsoleTextAttribute
_settextcursor*	SetConsoleCursorInfo
_settextposition*	SetConsoleCursorPosition
_settextwindow*	SetConsoleWindowInfo
_wrapon*	SetConsoleMode

Stream Routines

C Run time	Win32 Equivalent
clearerr	none
fclose	CloseHandle
_fcloseall	none
_fdopen	none
feof	none
ferror	none
fflush	FlushFileBuffers
fgetc	none
_fgetchar	none
fgetpos	none
fgets	none
_fileno	none
_flushall	none
fopen	CreateFile
fprintf	none
fputc	none
_fputchar	none
fputs	none
fread	ReadFile
freopen (std handles)	SetStdHandle
fscanf	None
fseek	SetFilePointer
fsetpos	SetFilePointer
_fsopen	CreateFile
ftell	SetFilePointer (check return value)
fwrite	WriteFile
getc	None
getchar	None
gets	None
_getw	None
printf	None
putc	None
putchar	None
puts	None
_putw	None
rewind	SetFilePointer
_rmtmp	None
scanf	None
setbuf	None
setvbuf	None
_snprintf	None
sprintf	Wsprintf
sscanf	None
_tempnam	GetTempFileName
tmpfile	None
tmpnam	GetTempFileName
ungetc	None
vfprintf	None
vprintf	None
_vsnprintf	None
vsprintf	Wvsprintf

Low-Level I/O

C Run time	Win32 Equivalent
_close	_lclose, CloseHandle
_commit	FlushFileBuffers
_creat	_lcreat, CreateFile
_dup	DuplicateHandle
_dup2	none
_eof	none
_lseek	_llseek, SetFilePointer
_open	_lopen, CreateFile
_read	_lread, ReadFile
_sopen	CreateFile
_tell	SetFilePointer (check return value)
_write	_lread

Console and Port I/O Routines

C Run time	Win32 Equivalent
_cgets	none
_cprintf	none
_cputs	none
_cscanf	none
_getch	ReadConsoleInput
_getche	ReadConsoleInput
_inp	none
_inpw	none
_kbhit	PeekConsoleInput
_outp	none
_outpw	none
_putch	WriteConsoleInput
_ungetch	none

Memory Allocation

C Run time	Win32 Equivalent
_alloca	none
_bfreeseg*	none
_bheapseg*	none
calloc	GlobalAlloc
_expand	none
free	GlobalFree
_freect*	GlobalMemoryStatus
_halloc*	GlobalAlloc
_heapadd	none
_heapchk	none
_heapmin	none
_heapset	none
_heapwalk	none
_hfree*	GlobalFree
malloc	GlobalAlloc
_memavl	GlobalMemoryStatus
_memmax	GlobalMemoryStatus
_msize*	GlobalSize
realloc	GlobalReAlloc
_set_new_handler	none
_set_hnew_handler*	None
_stackavail*	None

Process and Environment Control Routines

C Run time	Win32 Equivalent
abort	none
assert	none
atexit	none
_cexit	none
_c_exit	none
_exec functions	none
exit	ExitProcess
_exit	ExitProcess
getenv	GetEnvironmentVariable
_getpid	GetCurrentProcessId
Longjmp	none
_onexit	none
Perror	FormatMessage
_putenv	SetEnvironmentVariable
Raise	RaiseException
Setjmp	none
signal (ctrl-c only)	SetConsoleCtrlHandler
_spawn functions	CreateProcess
system	CreateProcess

String Manipulation

C Run time	Win32 Equivalent
strcat, wcscat	lstrcat
strchr, wcschr	none
strcmp, wcscmp	lstrcmp
strcpy, wcscpy	lstrcpy
strcspn, wcscspn	none
_strdup, _wcsdup	none
Strerror	FormatMessage
_strerror	FormatMessage
_stricmp, _wcsicmp	lstrcmpi
Strlen, wcslen	lstrlen
_strlwr, _wcslwr	CharLower, CharLowerBuffer
Strncat, wcsncat	none
Strncmp, wcsncmp	none
Strncpy, wcsncpy	none
_strnicmp, _wcsnicmp	none
_strnset, _wcsnset	FillMemory, ZeroMemory
strpbrk, wcspbrk	none
strrchr, wcsrchr	none
_strrev, _wcsrev	none
_strset, _wcsset	FillMemory, ZeroMemory
strspn, wcsspn	none
strstr, wcsstr	none
strtok, wcstok	none
_strupr, _wcsupr	CharUpper, CharUpperBuffer

MS-DOS Interface

C Run time	Win32 Equivalent
_bdos*	none
_chain_intr*	none
_disable*	none
_dos_allocmem*	GlobalAlloc
_dos_close*	CloseHandle
_dos_commit*	FlushFileBuffers
_dos_creat*	CreateFile
_dos_creatnew*	CreateFile
_dos_findfirst*	FindFirstFile
_dos_findnext*	FindNextFile
_dos_freemem*	GlobalFree
_dos_getdate*	GetSystemTime
_dos_getdiskfree*	GetDiskFreeSpace
_dos_getdrive*	GetCurrentDirectory
_dos_getfileattr*	GetFileAttributes
_dos_getftime*	GetFileTime
_dos_gettime*	GetSystemTime
_dos_getvect*	none
_dos_keep*	none
_dos_open*	OpenFile
_dos_read*	ReadFile
_dos_setblock*	GlobalReAlloc
_dos_setdate*	SetSystemTime
_dos_setdrive*	SetCurrentDirectory
_dos_setfileattr*	SetFileAttributes
_dos_setftime*	SetFileTime
_dos_settime*	SetSystemTime
_dos_setvect*	none
_dos_write*	WriteFile
_dosexterr*	GetLastError
_enable*	none
_FP_OFF*	none
_FP_SEG*	none
_harderr*	See Note 1
_hardresume*	See Note 1
_hardretn*	See Note 1
_int86*	none
_int86x*	none
_intdos*	none
_intdosx*	none
_segread*	none

Time

C Run time	Win32 Equivalent
asctime	See Note 2
clock	See Note 2
ctime	See Note 2
difftime	See Note 2
_ftime	See Note 2
_getsystime	GetLocalTime
gmtime	See Note 2
localtime	See Note 2
mktime	See Note 2
_strdate	See Note 2
_strtime	See Note 2
time	See Note 2
_tzset	See Note 2
_utime	SetFileTime

Virtual Memory Allocation

C Run time	Win32 Equivalent
_vfree*	See Note 3
_vheapinit*	See Note 3
_vheapterm*	See Note 3
_vload*	See Note 3
_vlock*	See Note 3
_vlockcnt*	See Note 3
_vmalloc*	See Note 3
_vmsize*	See Note 3
_vrealloc*	See Note 3
_vunlock*	See Note 3

32-Bit C Run Time

C Run time	Win32 Equivalent
_beginthread	CreateThread
_cwait	WaitForSingleObject w/ GetExitCodeProcess
_endthread	ExitThread
_findclose	FindClose
_findfirst	FindFirstFile
_findnext	FindNextFile
_futime	SetFileTime
_get_osfhandle	none
_open_osfhandle	none
_pclose	See Note 4
_pipe	CreatePipe
_popen	See Note 4

Note 1: The _harderr functions do not exist in the Win32 API. However, much of their functionality is available through structured exception handling.

Note 2: The time functions are based on a format that is not used in Win32. There are specific Win32 time functions that are documented in the Help file.

Note 3: The virtual memory functions listed in this document are specific to the MS-DOS environment and were written to access memory beyond the 640K of RAM available in MS-DOS. Because this limitation does not exist in Win32, the standard memory allocation functions should be used.

Note 4: While _pclose() and _popen() do not have direct Win32 equivalents, you can (with some work) simulate them with the following calls:

 _popen	CreatePipe
		CreateProcess

 _pclose	WaitForSingleObject
		CloseHandle

Note 5: GetFileInformationByHandle() is the Win32 equivalent for the _fstat() C Run-time function. However, GetFileInformationByHandle() is not supported by Win32s version 1.1. It is supported in Win32s 1.2. GetFileSize(), GetFileAttributes(), GetFileTime(), and GetFileTitle() are supported by Win32s 1.1 and 1.2.

Note 6: There are Win32 Buffer-Manipulation Routines that are actually not document but exist in kernel32.dll. Win32 functions such as FillMemory, CopyMemory, MoveMemory, and ZeroMemory are all actually macros that use the CLIB equivalents. After removing all default libraries we no longer have the CLIB, therefore we must use an alternative. RtlFillMemory, RtlMoveMemory, and RtlZeroMemory are also macros that use CLIB, although these functions actually do exist in kernel32.dll as Win32 API calls. Even though they exist they are not document and chances are that there may indeed be a reason behind that. These functions may be missing in some versions of Windows and are not support by Microsoft. A solution to this is to write your own Buffer-Manipulation Routines.

The following example is a header file that contains the source code to FillMemory, MoveMemory, CopyMemory, and ZeroMemory.

//**********************************************************************
// File: buffer.h			Last Modified:	03/02/01
//				Modified by:	PM
//
// Purpose:      Custom Buffer-Manipulation Routines
//
// Developed By: Piotr Mintus 2001
//**********************************************************************

#ifndef _BUFFER_H_
#define _BUFFER_H_

#ifdef FillMemory
#undef FillMemory
#endif
#ifdef ZeroMemory
#undef ZeroMemory
#endif
#ifdef CopyMemory
#undef CopyMemory
#endif
#ifdef MoveMemory
#undef MoveMemory
#endif

__forceinline
void FillMemory(void *dest,unsigned __int8 c,unsigned __int32 count)
{
unsigned __int32	size32=count>>2;
unsigned __int32	fill=(c<<24|c<<16|c<<8|c);
unsigned __int32	*dest32=(unsigned __int32*)dest;

switch( (count-(size32<<2)) )
{
case 3:	((unsigned __int8*)dest)[count - 3] = c;
case 2:	((unsigned __int8*)dest)[count - 2] = c;
case 1:	((unsigned __int8*)dest)[count - 1] = c;
}

while( size32-- > 0 )
*(dest32++) = fill;

}  /* FillMemory */

#define ZeroMemory(dest,count) FillMemory(dest,0,count)

__forceinline
void CopyMemory(void *dest,const void *src,unsigned __int32 count)
{
unsigned __int32	size32=count>>2;
unsigned __int32	*dest32=(unsigned __int32*)dest;
unsigned __int32	*src32=(unsigned __int32*)src;

switch( (count-(size32<<2)) )
{
case 3:	((unsigned __int8*)dest)[count-1] =
((unsigned __int8*)src)[count-1];
case 2:	((unsigned __int8*)dest)[count-2] =
((unsigned __int8*)src)[count-2];
case 1:	((unsigned __int8*)dest)[count-3] =
((unsigned __int8*)src)[count-3];
}

while( size32-- > 0 )
dest32[size32] = src32[size32];

}  /* CopyMemory */

__forceinline
void MoveMemory(void *dest,const void *src,unsigned __int32 count)
{
unsigned __int32	size32=count>>2,i;
unsigned __int32	*dest32=(unsigned __int32*)dest;
unsigned __int32	*src32=(unsigned __int32*)src;

if( dest > src )
{
switch( (count-(size32<<2)) )
{
case 3:	((unsigned __int8*)dest)[count-1] =
((unsigned __int8*)src)[count-1];
case 2:	((unsigned __int8*)dest)[count-2] =
((unsigned __int8*)src)[count-2];
case 1:	((unsigned __int8*)dest)[count-3] =
((unsigned __int8*)src)[count-3];
}

while( size32-- > 0 )
dest32[size32] = src32[size32];
}
else
{
for(i=0;i<size32;i++)
*(dest32++) = *(src32++);

switch( (count-(size32<<2)) )
{
case 3:	((unsigned __int8*)dest)[count-3] =
((unsigned __int8*)src)[count-3];
case 2:	((unsigned __int8*)dest)[count-2] =
((unsigned __int8*)src)[count-2];
case 1:	((unsigned __int8*)dest)[count-1] =
((unsigned __int8*)src)[count-1];
}
}

}  /* MoveMemory */

#endif // _BUFFER_H_

Now you can freely use FillMemory, MoveMemory, CopyMemory, and ZeroMemory within your application.

Observation: The preceding source code uses the __forceinline keyword. This will achieve greater speed. If small size is desired over speed, please remove the keyword and use the preceding source as normal functions.

Bibliography:

http://www.hailstorm.net/papers/smallwin32.htm

http://support.microsoft.com/default.aspx?scid=kb;EN-US;q99456

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Win32 Equivalents for C Run-Time Functions

Edited by:
Beyond2000!

March, 17, 2.002