Windows, Unix and ANSI C API Comparison

1. I/O

1. 1 File & Directory

Subject	Windows	UNIX	C Library	Comments
Console I/O	AllocConsole	terminal I/O	N/A
Console I/O	FreeConsole	terminal I/O	N/A
Console I/O	ReadConsole	read	getc, scanf, gets
Console I/O	SetConsoleMode	ioctl	N/A
Console I/O	WriteConsole	write	putc, printf, puts
Directory Mgt	CreateDirectory	mkdir*	N/A	Make a new directory
Directory Mgt	FindClose	closedir*	N/A	Close a directory search handle
Directory Mgt	FindFirstFile	opendir*, readdir*	N/A	Find first file matching a pattern
Directory Mgt	FindNextFile	readdir*	N/A	Find subsequent files
Directory Mgt	GetCurrentDirectory	getcwd*	N/A
Directory Mgt	GetFullPathName	N/A	N/A
Directory Mgt	GetSystemDirectory	Well-known pathnames	N/A
Directory Mgt	RemoveDirectory	rmdir, unlink*	remove
Directory Mgt	SearchPath	Use opendir, readdir	N/A	Search for a file on a specified path
Directory Mgt	SetCurrentDirectory	chdir*, fchdir	N/A	Change the working directory
Error Handling	FormatMessage	strerror	perror
Error Handling	GetLastError	errno	errno	Global variable
Error Handling	SetLastError	errno	errno	Global variable
File Locking	LockFile	fcntl (cmd=F_GETLK, ..)	N/A
File Locking	LockFileEx	fcntl (cmd=F_GETLK, ..)	N/A
File Locking	UnlockFile	fcntl (cmd=F_GETLK, ..)	N/A
File Locking	UnlockFileEx	fcntl (cmd=F_GETLK, ..)	N/A
File System	CloseHandle (file handle)	close*	fclose	CloseHandle is not limited to files
File System	CopyFile	open; read; write; close	fopen; fread; fwrite; fclose	Duplicate a file
File System	CreateFile	open*, creat*	fopen	Open/create a file
File System	DeleteFile	unlink*	remove	Delete a file
File System	FlushFileBuffers	fsynch	fflush	Write file buffers
File System	GetFileAttributes	stat*, fstat*, lstat	N/A
File System	GetFileInformationByHandle	stat*, fstat*, lstat	N/A	Fill structure with file info
File System	GetFileSize	stat*, fstat*, lstat	ftell, fseek	Get length of file in bytes
File System	GetFileTime	stat*, fstat*, lstat	N/A
File System	GetFileType	stat*, fstat*, lstat	N/A	Check for character stream device or file
File System	GetStdHandle	Use file desc 0, 1, or 2	Use stdin, stdout,stderr
File System	GetTempFileName	Use C library	tmpnam	Create a unique file name
File System	GetTempFileName, CreateFile	Use C library	tmpfile	Create a temporary file
File System	GetTempPath	/temp path	N/A	Directory for temp files
File System	MoveFile, MoveFileEx	Use C library	rename	Rename a file or directory
File System	CreateHardLink	link, unlink*	N/A	Windows does not support links
File System	N/A	symlink	N/A	Create a symbolic link
File System	N/A	readlink	N/A	Read name in a symbolic link
File System	N/A, ReadFile returns 0 bytes	N/A, read returns 0 bytes	feof	Rest for end of file
File System	N/A, use multiple ReadFiles	readv	N/A, use multiplefreads	Scatter read
File System	N/A, use multiple WriteFiles	writev	N/A, use multiplefwrites	Gather write
File System	ReadFile	read	fread	Read data from a file
File System	SetEndOfFile	chsize*	N/A
File System	SetFileAttributes	fcntl	N/A
File System	SetFilePointer	lseek	fseek	Set file pointer
FileSystem	SetFilePointer (to 0)	lseek (0)	rewind
File System	SetFileTime	utime*	N/A
File System	SetStdHandle	close, dup*,dup2*, or fcntl	freopen	dup2 or fcntl
File System	WriteFile	write	fwrite	Write data to a file

1.2 Async I/O

Subject	Windows	UNIX	C Library	Comments
Asynch I/O	GetOverlappedResult	N/A	N/A
Asynch I/O	ReadFileEx	N/A	N/A	Extended I/O with completion routine
Asynch I/O	SleepEx	N/A	N/A	Alertable wait
Asynch I/O	WaitForMultipleObjects (file handles)	poll, select	N/A
Asynch I/O	WaitForMultipleObjectsEx	N/A	N/A	Alertable wait
Asynch I/O	WriteFileEx	N/A	N/A	Extended I/O with completion routine
Asynch I/O	WaitForSingleObjectEx	waitpid	N/A	Alertable wait

2. Memory & DLL

Subject	Windows	UNIX	C Library
Mapped Files	CreateFileMapping	shmget	N/A
Mapped Files	MapViewOfFile	mmap, shmat	N/A
Mapped Files	MapViewOfFileEx	mmap, shmat	N/A
Mapped Files	OpenFileMapping	shmget	N/A
Mapped Files	UnmapViewOfFile	munmap, shmdt, shmctl	N/A
Memory Mgt	GetProcessHeap	N/A	N/A
Memory Mgt	GetSystemInfo	N/A	N/A
Memory Mgt	HeapAlloc	sbrk, brk, or C library	malloc, calloc
Memory Mgt	HeapCreate	N/A	N/A
Memory Mgt	HeapDestroy	N/A	N/A
Memory Mgt	HeapFree	Use C library	free
Memory Mgt	HeapReAlloc	Use C library	realloc
Memory Mgt	HeapSize	N/A	N/A
Shared Memory	CloseHandle (map handle)	shmctl	N/A
Shared Memory	CreateFileMapping, OpenFileMapping	shmget	N/A
Shared Memory	MapViewOfFile	shmat	N/A
Shared Memory	UnmapViewOfFile	shmdt	N/A
DLLs	LoadLibrary	dlopen	N/A
DLLs	FreeLibrary	dlclose	N/A
DLLs	GetProcAddress	dlsyn	N/A
DLLs	DllMain	pthread_once	N/A

3. Process & Thread

3.1 Process

Subject	Windows	UNIX	C Library	Comments
Process Mgt	CreateProcess	fork (); execl ()*, system()	N/A	There are 6 execxxfunctions
Process Mgt	ExitProcess	_exit	exit
Process Mgt	GetCommandLine	argv []	argv []
Process Mgt	GetCurrentProcess	getpid*	N/A
Process Mgt	GetCurrentProcessId	getpid*	N/A
Process Mgt	GetEnvironmentStrings	N/A	getenv
Process Mgt	GetEnvironmentVariable	N/A	getenv
Process Mgt	GetExitCodeProcess	wait, waitpid	N/A
Process Mgt	GetProcessTimes	times, wait3, wait4	N/A
Process Mgt	GetProcessWorkingSetSize	wait3, wait4	N/A
Process Mgt	N/A	execl*, execv*, execle*, execve*, execlp*, execvp*	N/A	Windows does not have a direct equivalent
Process Mgt	N/A	fork, vfork	N/A	Windows does not have a direct equivalent
Process Mgt	N/A	getppid	N/A	No parent/child relationships in Windows
Process Mgt	N/A	getgid, getegid	N/A	No process groups in Windows
Process Mgt	N/A	getpgrp	N/A
Process Mgt	N/A	setpgid	N/A
Process Mgt	N/A	setsid	N/A
Process Mgt	N/A	tcgetpgrp	N/A
Process Mgt	N/A	tcsetpgrp	N/A
Process Mgt	OpenProcess	N/A	N/A
Process Mgt	SetEnvironmentVariable	putenv	N/A	putenv is not part of the Standard C library
Process Mgt	TerminateProcess	kill	N/A
Synch: Process	WaitForMultipleObjects(process handles)	waitpid	N/A
Synch: Process	WaitForSingleObject(process handle)	wait, waitpid	N/A
Timers	KillTimer	alarm (0)	N/A
Timers	SetTimer	alarm	N/A
Timers	Sleep	sleep	N/A
Timers	Sleep	poll or select, no file descriptor	N/A

3.2 Thread

Subject	Windows	UNIX/Pthreads	Comments
Thread Mgt	CreateRemoteThread	N/A
TLS	TlsAlloc	pthread_key_alloc
TLS	TlsFree	pthread_key_delete
TLS	TlsGetValue	pthread_getspecific
TLS	TlsSetValue	pthread_setspecific
Thread Mgt	CreateThread, _beginthreadex	pthread_create
Thread Mgt	ExitThread, _endthreadex	pthread_exit
Thread Mgt	GetCurrentThread	pthread_self
Thread Mgt	GetCurrentThreadId	N/A
Thread Mgt	GetExitCodeThread	pthread_yield
Thread Mgt	ResumeThread	N/A
Thread Mgt	SuspendThread	N/A
Thread Mgt	TerminateThread	pthread_cancel	pthread_cancel is safer
Thread Mgt	WaitForSingleObject(thread handle)	pthread_join
Thread Priority	GetPriorityClass	pthread_attr_getschedpolicy, getpriority
Thread Priority	GetThreadPriority	pthread_attr_getschedparam
Thread Priority	SetPriorityClass	pthread_attr_setschedpolicy, setpriority, nice
Thread Priority	SetThreadPriority	pthread_attr_setschedparam
Note: Pthreads, while a part of all modern UNIX offerings, are available on non-UNIX systems as well.

3.3 Synchronization

Subject	Windows	UNIX/Pthreads	Comments
Synch: CritSec	DeleteCriticalSection	Use mutexes to emulate critical sections. Some systems provide proprietary equivalents.	C library is not applicable
Synch: CritSec	EnterCriticalSection		C library is not applicable
Synch: CritSec	InitializeCriticalSection
Synch: CritSec	LeaveCriticalSection
Synch: Event	CloseHandle (event handle)	pthread_cond_destroy
Synch: Event	CreateEvent	pthread_cond_init
Synch: Event	PulseEvent	pthread_cond_signal	Manual-reset event
Synch: Event	ResetEvent	N/A
Synch: Event	SetEvent	pthread_cond_broadcast	Auto-reset event
Synch: Event	WaitForSingleObject (event handle)	pthread_cond_wait
Synch: Event	WaitForSingleObject (event handle)	pthread_timed_wait
Synch: Mutex	CloseHandle (mutex handle)	pthread_mutex_destroy
Synch: Mutex	CreateMutex	pthread_mutex_init
Synch: Mutex	ReleaseMutex	pthread_mutex_unlock
Synch: Mutex	WaitForSingleObject(mutex handle)	pthread_mutex_lock
Synch: Sem	CreateSemaphore	semget
Synch: Sem	N/A	semctl	Windows does not directly support all these options
Synch: Sem	OpenSemaphore	semget
Synch: Sem	ReleaseSemaphore	semop (+)
Synch: Sem	WaitForSingleObject(semaphore handle)	semop (-)	Windows can wait for only one count

3.4 IPC

Subject	Windows	UNIX	C Library	Comments
IPC	CallNamedPipe	N/A	N/A	CreateFile, WriteFile, ReadFile, CloseHandle
IPC	CloseHandle (pipe handle)	close, msgctl	pclose	Not part of the Standard C library—see Stevens
IPC	ConnectNamedPipe	N/A	N/A
IPC	CreateMailslot	N/A	N/A
IPC	CreateNamedPipe	mkfifo, msgget	N/A
IPC	CreatePipe	pipe	popen	Not part of the Standard C library—see Stevens
IPC	DuplicateHandle	dup, dup2, orfcntl	N/A	Or use file names CONIN$, CONOUT$
IPC	GetNamedPipeHandleState	stat, fstat, lstat64	N/A
IPC	GetNamedPipeInfo	stat, fstat, lstat	N/A
IPC	ImpersonateNamedPipeClient	N/A	N/A
IPC	PeekNamedPipe	N/A	N/A
IPC	ReadFile (named pipe handle)	read (fifo), msgsnd	N/A
IPC	RevertToSelf	N/A	N/A
IPC	SetNamedPipeHandleState	N/A	N/A
IPC	TransactNamedPipe	N/A	N/A	WriteFile; ReadFile
IPC	WriteFile (named pipe handle)	write (fifo), msgrcv	N/A
Misc.	GetComputerName	uname	N/A
Misc.	SetComputerName	N/A	N/A
Security	SetNamedPipeIdentity	Use directory sticky bit	N/A

4. Misc

4.1 Security

Subject	Windows	UNIX	Comments
Security	AddAccessAllowedAce	chmod, fchmod	C library does not support security
Security	AddAccessDeniedAce	chmod, fchmod
Security	AddAuditAce	N/A
Security	CreatePrivateObjectSecurity	N/A
Security	DeleteAce	chmod, fchmod
Security	DestroyPrivateObjectSecurity	N/A
Security	GetAce	stat*, fstat*, lstat
Security	GetAclInformation	stat*, fstat*, lstat
Security	GetFileSecurity	stat*, fstat*, lstat
Security	GetPrivateObjectSecurity	N/A
Security	GetSecurityDescriptorDacl	stat*, fstat*, lstat
Security	GetUserName	getlogin
Security	InitializeAcl	N/A
Security	InitializeSecurityDescriptor	Umask
Security	LookupAccountName	getpwnam, getgrnam
Security	LookupAccountSid	getpwuid, getuid, geteuid
Security	N/A	getpwend, setpwent, endpwent
Security	N/A	getgrent, setgrent, endgrent
Security	N/A	Setuid, seteuid, setreuid
Security	N/A	Setgid, setegid, setregid
Security	OpenProcessToken	getgroups, setgroups, initgroups
Security	SetFileSecurity	chmod*, fchmod
Security	SetPrivateObjectSecurity	N/A
Security	SetSecurityDescriptorDacl	Umask
Security	SetSecurityDescriptorGroup	chown, fchown, lchown
Security	SetSecurityDescriptorOwner	chown, fchown, lchown
Security	SetSecurityDescriptorSacl	N/A

4.2 Exception Handling

Subject	Windows	UNIX	C Library
SEH	_try – _except	Use C library signals	Use C library signals
SEH	_try – _finally	Use C library signals	Use C library signals
SEH	AbnormalTermination	Use C library signals	Use C library signals
SEH	GetExceptionCode	Use C library signals	Use C library signals
SEH	RaiseException	Use C library signals	signal, raise
Signals	Use _finally block	Use C library	atexit
Signals	Use C library or terminate process	kill	raise
Signals	Use C library	Use C library	signal
Signals	Use SEH, VEH	sigemptyset	N/A
Signals	Use SEH, VEH	sigfillset	N/A
Signals	Use SEH, VEH	sigaddset	N/A
Signals	Use SEH, VEH	sigdelset	N/A
Signals	Use SEH, VEH	sigismember	N/A
Signals	Use SEH, VEH	sigprocmask	N/A
Signals	Use SEH, VEH	sigpending	N/A
Signals	Use SEH, VEH	sigaction	N/A
Signals	Use SEH, VEH	sigsetjmp	N/A
Signals	Use SEH, VEH	siglongjmp	N/A
Signals	Use SEH, VEH	sigsuspendf	N/A
Signals	Use SEH, VEH	psignal	N/A
Signals	Use SEH, VEH, or C library	Use C library	abort
Note: Many UNIX vendors provide proprietary exception handling capabilities.

4.3 System Information & Time

Subject	Windows	UNIX	C Library	Comments
System Info	GetDiskFreeSpace	N/A	N/A
System Info	GetSystemInfo	getrusage	N/A
System Info	GetVersion	uname	N/A
System Info	GetVolumeInformation	N/A	N/A
System Info	GlobalMemoryStatus	getrlimit	N/A
System Info	Various defined constants	sysconf, pathconf, fpathconf	N/A
Time	GetSystemTime	Use C library	time, gmtime
Time	See ls program,	Use C library	asctime
Time	CompareFileTime	Use C library	difftime	Compare "calendar" times
Time	FileTimeToLocalFileTime, FileTimeToSystemTime	Use C library	localtime
Time	FileTimeToSystemTime	Use C library	gmtime
Time	GetLocalTime	Use C library	time, localtime
Time	See touch program,	Use C library	strftime
Time	SetLocalTime	N/A	N/A
Time	SetSystemTime	N/A	N/A
Time	Subtract file times	Use C library	difftime
Time	SystemTimeToFileTime	Use C library	mktime

from: http://blogs.msdn.com/b/csliu/archive/2009/03/20/windows-unix-and-ansi-c-api-comparison.aspx