Os | API reference | Android Developers

public final class Os
extends Object

Access to low-level system functionality. Most of these are system calls. Most users will want to use higher-level APIs where available, but this class provides access to the underlying primitives used to implement the higher-level APIs.

The corresponding constants can be found in OsConstants.

Summary

Public methods
`static FileDescriptor`	`accept(FileDescriptor fd, InetSocketAddress peerAddress)` See accept(2).
`static boolean`	`access(String path, int mode)` See access(2).
`static void`	`bind(FileDescriptor fd, InetAddress address, int port)` See bind(2).
`static void`	`bind(FileDescriptor fd, SocketAddress address)` See bind(2).
`static void`	`chmod(String path, int mode)` See chmod(2).
`static void`	`chown(String path, int uid, int gid)` See chown(2).
`static void`	`close(FileDescriptor fd)` See close(2).
`static void`	`connect(FileDescriptor fd, InetAddress address, int port)` See connect(2).
`static void`	`connect(FileDescriptor fd, SocketAddress address)` See connect(2).
`static StructDlInfo`	`dladdr(long addr)` See dladdr(3)</>
`static FileDescriptor`	`dup(FileDescriptor oldFd)` See dup(2).
`static FileDescriptor`	`dup2(FileDescriptor oldFd, int newFd)` See dup2(2).
`static String[]`	`environ()` See environ(3).
`static void`	`execv(String filename, String[] argv)` See exec(3).
`static void`	`execve(String filename, String[] argv, String[] envp)` See execve(2).
`static void`	`fchmod(FileDescriptor fd, int mode)` See fchmod(2).
`static void`	`fchown(FileDescriptor fd, int uid, int gid)` See fchown(2).
`static int`	`fcntlInt(FileDescriptor fd, int cmd, int arg)` See fcntl(2).
`static void`	`fdatasync(FileDescriptor fd)` See fdatasync(2).
`static StructStat`	`fstat(FileDescriptor fd)` See fstat(2).
`static StructStatVfs`	`fstatvfs(FileDescriptor fd)` See fstatvfs(2).
`static void`	`fsync(FileDescriptor fd)` See fsync(2).
`static void`	`ftruncate(FileDescriptor fd, long length)` See ftruncate(2).
`static String`	`gai_strerror(int error)` See gai_strerror(3).
`static int`	`getegid()` See getegid(2).
`static String`	`getenv(String name)` See getenv(3).
`static int`	`geteuid()` See geteuid(2).
`static int`	`getgid()` See getgid(2).
`static SocketAddress`	`getpeername(FileDescriptor fd)` See getpeername(2).
`static int`	`getpid()` See getpid(2).
`static int`	`getppid()` See getppid(2).
`static SocketAddress`	`getsockname(FileDescriptor fd)` See getsockname(2).
`static StructTimeval`	`getsockoptTimeval(FileDescriptor fd, int level, int option)` See getsockopt(2).
`static int`	`gettid()` See gettid(2).
`static int`	`getuid()` See getuid(2).
`static byte[]`	`getxattr(String path, String name)` See getxattr(2)
`static String`	`if_indextoname(int index)` See if_indextoname(3).
`static int`	`if_nametoindex(String name)` See if_nametoindex(3).
`static InetAddress`	`inet_pton(int family, String address)` See inet_pton(3).
`static boolean`	`isatty(FileDescriptor fd)` See isatty(3).
`static void`	`kill(int pid, int signal)` See kill(2).
`static void`	`lchown(String path, int uid, int gid)` See lchown(2).
`static void`	`link(String oldPath, String newPath)` See link(2).
`static void`	`listen(FileDescriptor fd, int backlog)` See listen(2).
`static String[]`	`listxattr(String path)` See listxattr(2)
`static long`	`lseek(FileDescriptor fd, long offset, int whence)` See lseek(2).
`static StructStat`	`lstat(String path)` See lstat(2).
`static FileDescriptor`	`memfd_create(String name, int flags)` See memfd_create(2).
`static void`	`mincore(long address, long byteCount, byte[] vector)` See mincore(2).
`static void`	`mkdir(String path, int mode)` See mkdir(2).
`static void`	`mkfifo(String path, int mode)` See mkfifo(3).
`static void`	`mlock(long address, long byteCount)` See mlock(2).
`static long`	`mmap(long address, long byteCount, int prot, int flags, FileDescriptor fd, long offset)` See mmap(2).
`static void`	`msync(long address, long byteCount, int flags)` See msync(2).
`static void`	`munlock(long address, long byteCount)` See munlock(2).
`static void`	`munmap(long address, long byteCount)` See munmap(2).
`static FileDescriptor`	`open(String path, int flags, int mode)` See open(2).
`static FileDescriptor[]`	`pipe()` See pipe(2).
`static int`	`poll(StructPollfd[] fds, int timeoutMs)` See poll(2).
`static void`	`posix_fallocate(FileDescriptor fd, long offset, long length)` See posix_fallocate(3).
`static int`	`prctl(int option, long arg2, long arg3, long arg4, long arg5)` See prctl(2).
`static int`	`pread(FileDescriptor fd, byte[] bytes, int byteOffset, int byteCount, long offset)` See pread(2).
`static int`	`pread(FileDescriptor fd, ByteBuffer buffer, long offset)` See pread(2).
`static int`	`pwrite(FileDescriptor fd, byte[] bytes, int byteOffset, int byteCount, long offset)` See pwrite(2).
`static int`	`pwrite(FileDescriptor fd, ByteBuffer buffer, long offset)` See pwrite(2).
`static int`	`read(FileDescriptor fd, byte[] bytes, int byteOffset, int byteCount)` See read(2).
`static int`	`read(FileDescriptor fd, ByteBuffer buffer)` See read(2).
`static String`	`readlink(String path)` See readlink(2).
`static int`	`readv(FileDescriptor fd, Object[] buffers, int[] offsets, int[] byteCounts)` See readv(2).
`static int`	`recvfrom(FileDescriptor fd, byte[] bytes, int byteOffset, int byteCount, int flags, InetSocketAddress srcAddress)` See recvfrom(2).
`static int`	`recvfrom(FileDescriptor fd, ByteBuffer buffer, int flags, InetSocketAddress srcAddress)` See recvfrom(2).
`static int`	`recvmsg(FileDescriptor fd, StructMsghdr msg, int flags)` See recvmsg(2).
`static void`	`remove(String path)` See remove(3).
`static void`	`removexattr(String path, String name)` See removexattr(2).
`static void`	`rename(String oldPath, String newPath)` See rename(2).
`static long`	`sendfile(FileDescriptor outFd, FileDescriptor inFd, Int64Ref offset, long byteCount)` See sendfile(2).
`static int`	`sendmsg(FileDescriptor fd, StructMsghdr msg, int flags)` See sendmsg(2).
`static int`	`sendto(FileDescriptor fd, byte[] bytes, int byteOffset, int byteCount, int flags, SocketAddress address)` See sendto(2).
`static int`	`sendto(FileDescriptor fd, byte[] bytes, int byteOffset, int byteCount, int flags, InetAddress inetAddress, int port)` See sendto(2).
`static int`	`sendto(FileDescriptor fd, ByteBuffer buffer, int flags, InetAddress inetAddress, int port)` See sendto(2).
`static void`	`setegid(int egid)` This method was deprecated in API level 29. Android Applications do not have sufficient privileges to call this method.
`static void`	`setenv(String name, String value, boolean overwrite)` See setenv(3).
`static void`	`seteuid(int euid)` This method was deprecated in API level 29. Android Applications do not have sufficient privileges to call this method.
`static void`	`setgid(int gid)` This method was deprecated in API level 29. Android Applications do not have sufficient privileges to call this method.
`static int`	`setsid()` See setsid(2).
`static void`	`setsockoptInt(FileDescriptor fd, int level, int option, int value)` See setsockopt(2).
`static void`	`setsockoptTimeval(FileDescriptor fd, int level, int option, StructTimeval value)` See setsockopt(2).
`static void`	`setuid(int uid)` This method was deprecated in API level 29. Android Applications do not have sufficient privileges to call this method.
`static void`	`setxattr(String path, String name, byte[] value, int flags)` See setxattr(2)
`static void`	`shutdown(FileDescriptor fd, int how)` See shutdown(2).
`static FileDescriptor`	`socket(int domain, int type, int protocol)` See socket(2).
`static void`	`socketpair(int domain, int type, int protocol, FileDescriptor fd1, FileDescriptor fd2)` See socketpair(2).
`static StructStat`	`stat(String path)` See stat(2).
`static StructStatVfs`	`statvfs(String path)` See statvfs(2).
`static String`	`strerror(int errno)` See strerror(2).
`static String`	`strsignal(int signal)` See strsignal(3).
`static void`	`symlink(String oldPath, String newPath)` See symlink(2).
`static long`	`sysconf(int name)` See sysconf(3).
`static void`	`tcdrain(FileDescriptor fd)` See tcdrain(3).
`static void`	`tcsendbreak(FileDescriptor fd, int duration)` See tcsendbreak(3).
`static int`	`umask(int mask)` See umask(2).
`static StructUtsname`	`uname()` See uname(2).
`static void`	`unsetenv(String name)` See unsetenv(3).
`static int`	`write(FileDescriptor fd, byte[] bytes, int byteOffset, int byteCount)` See write(2).
`static int`	`write(FileDescriptor fd, ByteBuffer buffer)` See write(2).
`static int`	`writev(FileDescriptor fd, Object[] buffers, int[] offsets, int[] byteCounts)` See writev(2).

Inherited methods

From class java.lang.Object

`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`final Class<?>`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the object.
`final void`	`notify()` Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()` Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()` Returns a string representation of the object.
`final void`	`wait(long timeoutMillis, int nanos)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait()` Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

Public methods

fcntlInt

public static int fcntlInt (FileDescriptor fd, 
                int cmd, 
                int arg)

See fcntl(2).

Parameters
`fd`	`FileDescriptor`: This value cannot be `null`.
`cmd`	`int`
`arg`	`int`

Returns
`int`

Throws
`ErrnoException`

getegid

public static int getegid ()

See getegid(2).

Returns
`int`

geteuid

public static int geteuid ()

See geteuid(2).

Returns
`int`

getgid

public static int getgid ()

See getgid(2).

Returns
`int`

getpid

public static int getpid ()

See getpid(2).

Returns
`int`

getppid

public static int getppid ()

See getppid(2).

Returns
`int`

gettid

public static int gettid ()

See gettid(2).

Returns
`int`

getuid

public static int getuid ()

See getuid(2).

Returns
`int`

if_nametoindex

public static int if_nametoindex (String name)

See if_nametoindex(3).

Parameters
`name`	`String`

Returns
`int`

isatty

public static boolean isatty (FileDescriptor fd)

See isatty(3).

Parameters
`fd`	`FileDescriptor`

Returns
`boolean`

kill

public static void kill (int pid, 
                int signal)

See kill(2).

Parameters
`pid`	`int`
`signal`	`int`

Throws
`ErrnoException`

mincore

public static void mincore (long address, 
                long byteCount, 
                byte[] vector)

See mincore(2).

Parameters
`address`	`long`
`byteCount`	`long`
`vector`	`byte`

Throws
`ErrnoException`

mlock

public static void mlock (long address, 
                long byteCount)

See mlock(2).

Parameters
`address`	`long`
`byteCount`	`long`

Throws
`ErrnoException`

mmap

public static long mmap (long address, 
                long byteCount, 
                int prot, 
                int flags, 
                FileDescriptor fd, 
                long offset)

See mmap(2).

Parameters
`address`	`long`
`byteCount`	`long`
`prot`	`int`
`flags`	`int`
`fd`	`FileDescriptor`
`offset`	`long`

Returns
`long`

Throws
`ErrnoException`

msync

public static void msync (long address, 
                long byteCount, 
                int flags)

See msync(2).

Parameters
`address`	`long`
`byteCount`	`long`
`flags`	`int`

Throws
`ErrnoException`

munlock

public static void munlock (long address, 
                long byteCount)

See munlock(2).

Parameters
`address`	`long`
`byteCount`	`long`

Throws
`ErrnoException`

munmap

public static void munmap (long address, 
                long byteCount)

See munmap(2).

Parameters
`address`	`long`
`byteCount`	`long`

Throws
`ErrnoException`

poll

public static int poll (StructPollfd[] fds, 
                int timeoutMs)

See poll(2).

Note that in Lollipop this could throw an ErrnoException with EINTR. In later releases, the implementation will automatically just restart the system call with an appropriately reduced timeout.

Parameters
`fds`	`StructPollfd`
`timeoutMs`	`int`

Returns
`int`

Throws
`ErrnoException`

prctl

public static int prctl (int option, 
                long arg2, 
                long arg3, 
                long arg4, 
                long arg5)

See prctl(2).

Parameters
`option`	`int`
`arg2`	`long`
`arg3`	`long`
`arg4`	`long`
`arg5`	`long`

Returns
`int`

Throws
`ErrnoException`

sendto

public static int sendto (FileDescriptor fd, 
                byte[] bytes, 
                int byteOffset, 
                int byteCount, 
                int flags, 
                SocketAddress address)

See sendto(2).

Parameters
`fd`	`FileDescriptor`: This value cannot be `null`.
`bytes`	`byte`: This value cannot be `null`.
`byteOffset`	`int`
`byteCount`	`int`
`flags`	`int`
`address`	`SocketAddress`: This value may be `null`.

Returns
`int`

Throws
`ErrnoException`
`SocketException`

sendto

public static int sendto (FileDescriptor fd, 
                byte[] bytes, 
                int byteOffset, 
                int byteCount, 
                int flags, 
                InetAddress inetAddress, 
                int port)

See sendto(2).

Parameters
`fd`	`FileDescriptor`
`bytes`	`byte`
`byteOffset`	`int`
`byteCount`	`int`
`flags`	`int`
`inetAddress`	`InetAddress`
`port`	`int`

Returns
`int`

Throws
`ErrnoException`
`SocketException`

setegid

public static void setegid (int egid)

This method was deprecated in API level 29.
Android Applications do not have sufficient privileges to call this method.

See setegid(2).

Parameters
`egid`	`int`

Throws
`ErrnoException`

seteuid

public static void seteuid (int euid)

This method was deprecated in API level 29.
Android Applications do not have sufficient privileges to call this method.

See seteuid(2).

Parameters
`euid`	`int`

Throws
`ErrnoException`

setgid

public static void setgid (int gid)

This method was deprecated in API level 29.
Android Applications do not have sufficient privileges to call this method.

See setgid(2).

Parameters
`gid`	`int`

Throws
`ErrnoException`

setuid

public static void setuid (int uid)

This method was deprecated in API level 29.
Android Applications do not have sufficient privileges to call this method.

See setuid(2).

Parameters
`uid`	`int`

Throws
`ErrnoException`

sysconf

public static long sysconf (int name)

See sysconf(3).

Parameters
`name`	`int`

Returns
`long`

umask

public static int umask (int mask)

See umask(2).

Parameters
`mask`	`int`

Returns
`int`