net.openhft.posix

Interface PosixAPI

public interface PosixAPI

This interface provides a set of methods for interacting with POSIX APIs. It includes methods for file operations, memory management, and process scheduling.

Method Summary

Modifier and Type	Method and Description
default long	clock_gettime() Returns the current wall clock time in nanoseconds.
default long	clock_gettime(ClockId clockId) Returns the current wall clock time for a specific clock ID in nanoseconds.
long	clock_gettime(int clockId) Returns the current wall clock time for a specific clock ID in nanoseconds.
int	close(int fd) Closes a file descriptor.
default long	du(String filename) Calculates disk usage for a given filename.
int	fallocate(int fd, int mode, long offset, long length) Allocates space for a file descriptor.
void	free(long ptr) Frees allocated memory.
int	ftruncate(int fd, long offset) Truncates a file descriptor to a specified length.
int	get_nprocs_conf() Returns the number of configured processors.
int	get_nprocs() Returns the number of available processors.
int	getpid() Returns the process ID.
int	gettid() Returns the thread ID.
default long	gettimeofday() Returns the current wall clock time in microseconds.
int	gettimeofday(long timeval) Gets the current time of day.
int	lastError() Returns the last error code.
default String	lastErrorStr() Returns the last error message.
int	lockf(int fd, int cmd, long len) Locks a section of a file descriptor.
long	lseek(int fd, long offset, int whence) Repositions the read/write file offset.
default long	lseek(int fd, long offset, WhenceFlag whence) Repositions the read/write file offset.
int	madvise(long addr, long length, int advice) Advises the kernel about how to handle paging input/output.
default int	madvise(long addr, long length, MAdviseFlag advice) Advises the kernel about how to handle paging input/output.
long	malloc(long size) Allocates memory of a specified size.
default boolean	mlock(long addr, long length) Locks a range of the process's virtual address space into RAM.
default boolean	mlock2(long addr, long length, boolean lockOnFault) Locks a range of the process's virtual address space into RAM.
default void	mlockall(int flags) Locks all current and future pages into RAM.
default void	mlockall(MclFlag flags) Locks all current and future pages into RAM.
long	mmap(long addr, long length, int prot, int flags, int fd, long offset) Maps files or devices into memory.
default long	mmap(long addr, long length, MMapProt prot, MMapFlag flags, int fd, long offset) Maps files or devices into memory.
int	msync(long address, long length, int mode) Synchronizes changes to a file with the storage device.
default int	msync(long address, long length, MSyncFlag flags) Synchronizes changes to a file with the storage device.
int	munmap(long addr, long length) Unmaps files or devices from memory.
int	open(CharSequence path, int flags, int perm) Opens a file descriptor.
default int	open(CharSequence path, OpenFlag flags, int perm) Opens a file descriptor.
static PosixAPI	posix()
long	read(int fd, long dst, long len) Reads from a file descriptor.
default String	sched_getaffinity_summary(int pid) Returns a summary of the CPU affinity for a given process ID.
int	sched_getaffinity(int pid, int cpusetsize, long mask) Gets the CPU affinity for a process.
default int	sched_setaffinity_as(int pid, int cpu) Sets the CPU affinity for a process to a specific CPU.
default int	sched_setaffinity_range(int pid, int from, int to) Sets the CPU affinity for a process to a range of CPUs.
int	sched_setaffinity(int pid, int cpusetsize, long mask) Sets the CPU affinity for a process.
String	strerror(int errno) Returns the error message for a given error code.
static void	useNoOpPosixApi() Sets the PosixAPI to a no-op implementation.
long	write(int fd, long src, long len) Writes to a file descriptor.

Method Detail

posix

static PosixAPI posix()

Returns:

The fastest available PosixAPI implementation.

useNoOpPosixApi

static void useNoOpPosixApi()

Sets the PosixAPI to a no-op implementation.

close

int close(int fd)

Closes a file descriptor.

Parameters:

fd - The file descriptor to close.

Returns:

0 on success, -1 on error.

fallocate

int fallocate(int fd,
              int mode,
              long offset,
              long length)

Allocates space for a file descriptor.

Parameters:

fd - The file descriptor.

mode - The allocation mode.

offset - The offset in the file.

length - The length of the allocation.

Returns:

0 on success, -1 on error.

ftruncate

int ftruncate(int fd,
              long offset)

Truncates a file descriptor to a specified length.

Parameters:

fd - The file descriptor.

offset - The length to truncate to.

Returns:

0 on success, -1 on error.

lseek

default long lseek(int fd,
                   long offset,
                   WhenceFlag whence)

Repositions the read/write file offset.

Parameters:

fd - The file descriptor.

offset - The offset to seek to.

whence - The directive for how to seek.

Returns:

The resulting offset location measured in bytes from the beginning of the file.

lseek

long lseek(int fd,
           long offset,
           int whence)

Repositions the read/write file offset.

Parameters:

fd - The file descriptor.

offset - The offset to seek to.

whence - The directive for how to seek.

Returns:

The resulting offset location measured in bytes from the beginning of the file.

lockf

int lockf(int fd,
          int cmd,
          long len)

Locks a section of a file descriptor.

Parameters:

fd - The file descriptor.

cmd - The command to perform.

len - The length of the section to lock.

Returns:

0 on success, -1 on error.

madvise

default int madvise(long addr,
                    long length,
                    MAdviseFlag advice)

Advises the kernel about how to handle paging input/output.

Parameters:

addr - The address.

length - The length.

advice - The advice directive.

Returns:

0 on success, -1 on error.

madvise

int madvise(long addr,
            long length,
            int advice)

Advises the kernel about how to handle paging input/output.

Parameters:

addr - The address.

length - The length.

advice - The advice directive.

Returns:

0 on success, -1 on error.

mmap

default long mmap(long addr,
                  long length,
                  MMapProt prot,
                  MMapFlag flags,
                  int fd,
                  long offset)

Maps files or devices into memory.

Parameters:

addr - The address.

length - The length.

prot - The desired memory protection.

flags - The flags.

fd - The file descriptor.

offset - The offset.

Returns:

The starting address of the mapped area.

mmap

long mmap(long addr,
          long length,
          int prot,
          int flags,
          int fd,
          long offset)

Maps files or devices into memory.

Parameters:

addr - The address.

length - The length.

prot - The desired memory protection.

flags - The flags.

fd - The file descriptor.

offset - The offset.

Returns:

The starting address of the mapped area.

mlock

default boolean mlock(long addr,
                      long length)

Locks a range of the process's virtual address space into RAM.

Parameters:

addr - The address.

length - The length.

Returns:

false, indicating the operation is not supported.

mlock2

default boolean mlock2(long addr,
                       long length,
                       boolean lockOnFault)

Locks a range of the process's virtual address space into RAM.

Parameters:

addr - The address.

length - The length.

lockOnFault - Whether to lock on fault.

Returns:

false, indicating the operation is not supported.

mlockall

default void mlockall(MclFlag flags)

Locks all current and future pages into RAM.

Parameters:

flags - The flags.

mlockall

default void mlockall(int flags)

Locks all current and future pages into RAM.

Parameters:

flags - The flags.

msync

default int msync(long address,
                  long length,
                  MSyncFlag flags)

Synchronizes changes to a file with the storage device.

Parameters:

address - The address.

length - The length.

flags - The flags.

Returns:

0 on success, -1 on error.

msync

int msync(long address,
          long length,
          int mode)

Synchronizes changes to a file with the storage device.

Parameters:

address - The address.

length - The length.

mode - The synchronization mode.

Returns:

0 on success, -1 on error.

munmap

int munmap(long addr,
           long length)

Unmaps files or devices from memory.

Parameters:

addr - The address.

length - The length.

Returns:

0 on success, -1 on error.

open

default int open(CharSequence path,
                 OpenFlag flags,
                 int perm)

Opens a file descriptor.

Parameters:

path - The path to the file.

flags - The flags.

perm - The permissions.

Returns:

The file descriptor.

open

int open(CharSequence path,
         int flags,
         int perm)

Opens a file descriptor.

Parameters:

path - The path to the file.

flags - The flags.

perm - The permissions.

Returns:

The file descriptor.

read

long read(int fd,
          long dst,
          long len)

Reads from a file descriptor.

Parameters:

fd - The file descriptor.

dst - The destination address.

len - The number of bytes to read.

Returns:

The number of bytes read.

write

long write(int fd,
           long src,
           long len)

Writes to a file descriptor.

Parameters:

fd - The file descriptor.

src - The source address.

len - The number of bytes to write.

Returns:

The number of bytes written.

du

default long du(String filename)
         throws IOException

Calculates disk usage for a given filename.

Parameters:

filename - The filename to calculate disk usage for.

Returns:

The disk usage in bytes.

Throws:

IOException - If an I/O error occurs.

gettimeofday

int gettimeofday(long timeval)

Gets the current time of day.

Parameters:

timeval - The address of the timeval structure.

Returns:

0 on success, -1 on error.

sched_setaffinity

int sched_setaffinity(int pid,
                      int cpusetsize,
                      long mask)

Sets the CPU affinity for a process.

Parameters:

pid - The process ID.

cpusetsize - The size of the CPU set.

mask - The CPU set mask.

Returns:

0 on success, -1 on error.

sched_getaffinity

int sched_getaffinity(int pid,
                      int cpusetsize,
                      long mask)

Gets the CPU affinity for a process.

Parameters:

pid - The process ID.

cpusetsize - The size of the CPU set.

mask - The CPU set mask.

Returns:

0 on success, -1 on error.

sched_getaffinity_summary

default String sched_getaffinity_summary(int pid)

Returns a summary of the CPU affinity for a given process ID.

Parameters:

pid - The process ID.

Returns:

A summary of the CPU affinity as a string.

lastError

int lastError()

Returns the last error code.

Returns:

The last error code.

sched_setaffinity_as

default int sched_setaffinity_as(int pid,
                                 int cpu)

Sets the CPU affinity for a process to a specific CPU.

Parameters:

pid - The process ID.

cpu - The CPU to set affinity to.

Returns:

0 on success, -1 on error.

sched_setaffinity_range

default int sched_setaffinity_range(int pid,
                                    int from,
                                    int to)

Sets the CPU affinity for a process to a range of CPUs.

Parameters:

pid - The process ID.

from - The starting CPU.

to - The ending CPU.

Returns:

0 on success, -1 on error.

gettimeofday

default long gettimeofday()

Returns the current wall clock time in microseconds. Note that clock_gettime() is more accurate if available.

Returns:

The wall clock time in microseconds.

clock_gettime

default long clock_gettime()

Returns the current wall clock time in nanoseconds.

Returns:

The wall clock time in nanoseconds.

clock_gettime

default long clock_gettime(ClockId clockId)
                    throws IllegalArgumentException

Returns the current wall clock time for a specific clock ID in nanoseconds.

Parameters:

clockId - The clock ID.

Returns:

The wall clock time in nanoseconds.

Throws:

IllegalArgumentException - If the clock ID is invalid.

clock_gettime

long clock_gettime(int clockId)
            throws IllegalArgumentException

Returns the current wall clock time for a specific clock ID in nanoseconds.

Parameters:

clockId - The clock ID.

Returns:

The wall clock time in nanoseconds.

Throws:

IllegalArgumentException - If the clock ID is invalid.

malloc

long malloc(long size)

Allocates memory of a specified size.

Parameters:

size - The size of the memory to allocate.

Returns:

The address of the allocated memory.

free

void free(long ptr)

Frees allocated memory.

Parameters:

ptr - The address of the memory to free.

get_nprocs

int get_nprocs()

Returns the number of available processors.

Returns:

The number of available processors.

get_nprocs_conf

int get_nprocs_conf()

Returns the number of configured processors.

Returns:

The number of configured processors.

getpid

int getpid()

Returns the process ID.

Returns:

The process ID.

gettid

int gettid()

Returns the thread ID.

Returns:

The thread ID.

strerror

String strerror(int errno)

Returns the error message for a given error code.

Parameters:

errno - The error code.

Returns:

The error message.

lastErrorStr

default String lastErrorStr()

Returns the last error message.

Returns:

The last error message.