Mono implements a small subset of the Win32 API for some file system interaction, I/O, thread and process operations.
On Windows, Mono uses directly the services provided by the operating system. On other operating system it uses its own implementation (referred to as the "io-layer" or "wapi").
BindIoCompletionCallback
CloseHandle
closesocket
CopyFile
CreateDirectory
CreateEvent
CreateFile
CreateMutex
CreatePipe
CreateProcess
CreateProcessWithLogonW
CreateSemaphore
CreateThread
DeleteCriticalSection
DeleteFile
DuplicateHandle
EnterCriticalSection
EnumProcesses
EnumProcessModules
errno_to_WSA
ExitThread
FileTimeToSystemTime
FindClose
FindFirstFile
FindNextFile
FlushFileBuffers
FormatMessage
GetCurrentDirectory
GetCurrentProcess
GetCurrentProcessId
GetCurrentThread
GetCurrentThreadId
GetDiskFreeSpaceEx
GetDriveType
GetExitCodeProcess
GetExitCodeThread
GetFileAttributesEx
GetFileAttributes
GetFileSize
GetFileTime
GetFileType
GetFileVersionInfo
GetFileVersionInfoSize
GetLastError
GetLogicalDriveStrings
GetModuleBaseName
GetModuleFileNameEx
GetModuleInformation
GetPriorityClass
GetProcessId
GetProcessTimes
GetProcessWorkingSetSize
GetStdHandle
GetSystemInfo
GetTempPath
GetThreadContext
GetTickCount
ImpersonateLoggedOnUser
InitializeCriticalSectionAndSpinCount
InitializeCriticalSection
ioctlsocket
LeaveCriticalSection
LockFile
MoveFile
OpenEvent
OpenMutex
OpenProcess
OpenSemaphore
OpenThread
PulseEvent
QueryPerformanceCounter
QueryPerformanceFrequency
QueueUserAPC
ReadFile
ReleaseMutex
ReleaseSemaphore
RemoveDirectory
ReplaceFile
ResetEvent
ResumeThread
RevertToSelf
SetCriticalSectionSpinCount
SetCurrentDirectory
SetEndOfFile
SetEvent
SetFileAttributes
SetFilePointer
SetFileTime
SetLastError
SetPriorityClass
SetProcessWorkingSetSize
ShellExecuteEx
SignalObjectAndWait
SleepEx
Sleep
SuspendThread
TerminateProcess
TlsAlloc
TlsFree
TlsGetValue
TlsSetValue
TransmitFile
TryEnterCriticalSection
UnlockFile
VerLanguageName
VerQueryValue
WaitForInputIdle
WaitForMultipleObjectsEx
WaitForMultipleObjects
WaitForSingleObjectEx
WaitForSingleObject
WriteFile
WSACleanup
WSAGetLastError
WSAIoctl
WSARecv
WSASend
WSASetLastError
WSAStartup
The extended APIs provide access to a few internals of the WAPI stack that are not exposed through the standard Win32 APIs.
mono_once
wapi_clear_interruption
wapi_current_thread_desc
wapi_interrupt_thread
wapi_self_interrupt
wapi_thread_clear_wait_handle