SysInfo returns system information in Info. Returned information in Info includes:

uptime

Number of seconds since boot.

loads

1, 5 and 15 minute load averages.

totalram

total amount of main memory.

freeram

amount of free memory.

sharedram

amount of shared memory.

bufferram

amount of memory used by buffers.

totalswap

total amount of swapspace.

freeswap

amount of free swapspace.

procs

number of current processes.

Clone creates a child process which is a copy of the parent process, just like FpFork does. In difference with Fork, however, the child process shares some parts of it's execution context with its parent, so it is suitable for the implementation of threads: many instances of a program that share the same memory.

When the child process is created, it starts executing the function Func, and passes it Args. The return value of Func is either the explicit return value of the function, or the exit code of the child process.

The sp pointer points to the memory reserved as stack space for the child process. This address should be the top of the memory block to be used as stack.

The Flags determine the behaviour of the Clone call. The low byte of the Flags contains the number of the signal that will be sent to the parent when the child dies. This may be bitwise OR'ed with the following constants:

CLONE_VM

Parent and child share the same memory space, including memory (un)mapped with subsequent mmap calls.

CLONE_FS

Parent and child have the same view of the filesystem; the chroot, chdir and umask calls affect both processes.

CLONE_FILES

the file descriptor table of parent and child is shared.

CLONE_SIGHAND

the parent and child share the same table of signal handlers. The signal masks are different, though.

CLONE_PID

PArent and child have the same process ID.

Clone returns the process ID in the parent process, and -1 if an error occurred.

epoll_create creates a new epoll file descriptor. The size argument indicates to the kernel approximately how many structures should be allocated, but is by no means an upper limit.

On success, a file descriptor is returned that can be used in subsequent or calls, and should be closed using the fpClose call.

epoll_ctl performs the op operation on epoll file descriptor epfd. The operation will be monitored on file descriptor fd, and is optionally controlled by event.

op can be one of the following values:

EPOLL_CTL_ADD

EPOLL_CTL_MOD

EPOLL_CTL_DEL

The events field in event_data is a bitmask of one or more of the following values:

EPOLLIN

The file is ready for read operations

EPOLLOUT

The file is ready for write operations.

EPOLLPRI

Urgent data is available for read operations.

EPOLLERR

An error condition is signaled on the file descriptor.

EPOLLHUP

A Hang up happened on the file descriptor.

EPOLLET

Set the Edge Triggered behaviour for the file descriptor.

EPOLLONESHOT

Set One-Shot behaviour for the file descriptor. The event will be triggered only once.

epoll_wait waits for timeout milliseconds for an event to occur on epoll file descriptor epfd. If timeout is -1, it waits indefinitely, if timeour is zero, it does not wait, but returns immediatly, even if no events were detected.

On return, data for at most maxevents will be returned in the memory pointed to by events. The function returns the number of file descriptors for which events were reported. This can be zero if the timeout was reached.

FUTEX_OP Performs an operation on a futex:

FUTEX_OP := ((op and $F) shl 28) or  
            ((cmp and $F) shl 24) or 
            ((oparg and $FFF) shl 12) 
            or (cmparg and $FFF);

capget returns the capabilities of the indicated thread in header. The thread is identified by the process ID, or -1 for all caller (and child) process ID's.

Refer to the linux man pages (7 capabilities) for more info.

capget sets the capabilities of the indicated thread in header. The thread is identified by the process ID, or -1 for all caller (and child) process ID's.

Refer to the linux man pages (7 capabilities) for more info.

sync_file_range forces the linux kernel to write any data pages of a specified file (file descriptor fd) to disk. The range of the file is specified by the offset offset and the number of bytes nbytes. Options is an OR-ed combination of

SYNC_FILE_RANGE_WAIT_BEFORE

SYNC_FILE_RANGE_WRITE

SYNC_FILE_RANGE_WAIT_AFTER

If none is specified, the operation does nothing.

futex performs an operation on a memory futex as described in the kernel manual page for futex. The mutex is located at uaddr, the operation op is one of the following constants:

FUTEX_WAIT

FUTEX_WAKE

FUTEX_FD

FUTEX_REQUEUE

FUTEX_CMP_REQUEUE

The value to check for is indicated in val, and a timeout can be specified in timeout. The optional arguments addr2 and val3 are used only with the FUTEX_REQUEUE and FUTEX_CMP_REQUEUE operations.

In case of an error, -1 is return. All other return values must be interpreted according to the operation performed.

This call directly interfaces with the Linux kernel, more information can be found in the kernel manual pages.

inotify_event is the structure used to report changes in a directory. When reading a inotify file descriptor, one or more inotify_event records can be read from the file descriptor.

inotify_init1 initializes a new INotify file descriptor. The following options can be OR-ed and passed in flags:

IN_NONBLOCK

IN_CLOEXEC

inotify_add_watch can be used to add a watch to an initialized inotify file descriptor (fd). The file or directory to watch can be specified in the name parameter, and the events that must be reported can be specified in mask. The following flags can be specified:

IN_ACCESS

Data was read from file.

IN_MODIFY

Data was written to file.

IN_ATTRIB

File attributes changed.

IN_CLOSE_WRITE

File opened for write was closed

IN_CLOSE_NOWRITE

File opened for read was closed

IN_CLOSE

File was closed (read or write)

IN_OPEN

File was opened

IN_MOVED_FROM

File was moved away from watched directory

IN_MOVED_TO

File was moved into watched directory

IN_MOVE

File was moved (in or out of directory)

IN_CREATE

A file was created in the directory.

IN_DELETE

A file was deleted from the directory.

IN_DELETE_SELF

Directory or file under observation was deleted.

IN_MOVE_SELF

Directory or file under observation was moved.

IN_ALL_EVENTS

All possible events OR-ed together.

These events can be OR-ed with some flags, controlling the behaviour of the watch:

IN_ONLYDIR

Only watch filename if it is a directory.

IN_ISDIR

Event occurred against directory.

IN_DONT_FOLLOW

Do not follow symlinks

IN_MASK_ADD

Add events to existing watch (OR-ing the sets) if one exists.

IN_ONESHOT

Only report one event, then remove the watch.

On return, the function returns a watch descriptor, which will be reported in the structure's wd.