Section 2: System Calls

A B C D E F G I K L M N O P Q R S T U V W X
Section index

A

accept(2): accept a connection on a socket
accept4(2): accept a connection on a socket
access(2): check user's permissions for a file
acct(2): switch process accounting on or off
add_key(2): add a key to the kernel's key management facility
adjtimex(2): tune kernel clock
afs_syscall(2): unimplemented system calls
alarm(2): set an alarm clock for delivery of a signal
alloc_hugepages(2): allocate or free huge pages
arch_prctl(2): set architecture-specific thread state
arm_fadvise(2): predeclare an access pattern for file data
arm_fadvise64_64(2): predeclare an access pattern for file data
arm_sync_file_range(2): sync a file segment with disk

B

bdflush(2): start, flush, or tune buffer-dirty-flush daemon
bind(2): bind a name to a socket
bpf(2): perform a command on an extended BPF map or program
break(2): unimplemented system calls
brk(2): change data segment size

C

cacheflush(2): flush contents of instruction and/or data cache
capget(2): set/get capabilities of thread(s)
capset(2): set/get capabilities of thread(s)
chdir(2): change working directory
chmod(2): change permissions of a file
chown(2): change ownership of a file
chown32(2): change ownership of a file
chroot(2): change root directory
clock_adjtime(2): tune kernel clock
clock_getres(2): clock and time functions
clock_gettime(2): clock and time functions
clock_nanosleep(2): high-resolution sleep with specifiable clock
clock_settime(2): clock and time functions
clone(2): create a child process
__clone2(2): create a child process
clone2(2): create a child process
clone3(2): create a child process
close(2): close a file descriptor
close_range(2): close all file descriptors in a given range
connect(2): initiate a connection on a socket
copy_file_range(2): Copy a range of data from one file to another
creat(2): open and possibly create a file
create_module(2): create a loadable module entry

D

delete_module(2): unload a kernel module
dup(2): duplicate a file descriptor
dup2(2): duplicate a file descriptor
dup3(2): duplicate a file descriptor

E

epoll_create(2): open an epoll file descriptor
epoll_create1(2): open an epoll file descriptor
epoll_ctl(2): control interface for an epoll file descriptor
epoll_pwait(2): wait for an I/O event on an epoll file descriptor
epoll_pwait2(2): wait for an I/O event on an epoll file descriptor
epoll_wait(2): wait for an I/O event on an epoll file descriptor
eventfd(2): create a file descriptor for event notification
eventfd2(2): create a file descriptor for event notification
execve(2): execute program
execveat(2): execute program relative to a directory file descriptor
_Exit(2): terminate the calling process
_exit(2): terminate the calling process
exit(2): terminate the calling process
exit_group(2): exit all threads in a process

F

faccessat(2): check user's permissions for a file
faccessat2(2): check user's permissions for a file
fadvise64(2): predeclare an access pattern for file data
fadvise64_64(2): predeclare an access pattern for file data
fallocate(2): manipulate file space
fanotify_init(2): create and initialize fanotify group
fanotify_mark(2): add, remove, or modify an fanotify mark on a filesyste...
fattach(2): unimplemented system calls
fchdir(2): change working directory
fchmod(2): change permissions of a file
fchmodat(2): change permissions of a file
fchown(2): change ownership of a file
fchown32(2): change ownership of a file
fchownat(2): change ownership of a file
fcntl(2): manipulate file descriptor
fcntl64(2): manipulate file descriptor
FD_ZERO(2): synchronous I/O multiplexing
fdatasync(2): synchronize a file's in-core state with storage device
fdetach(2): unimplemented system calls
fgetxattr(2): retrieve an extended attribute value
File::FcntlLock(3pm): File locking with fcntl(2)
File::FcntlLock::Inline(3pm): File locking with fcntl(2)
File::FcntlLock::Pure(3pm): File locking with fcntl(2)
File::FcntlLock::XS(3pm): File locking with fcntl(2)
finit_module(2): load a kernel module
flistxattr(2): list extended attribute names
flock(2): apply or remove an advisory lock on an open file
fork(2): create a child process
free_hugepages(2): allocate or free huge pages
fremovexattr(2): remove an extended attribute
fsetxattr(2): set an extended attribute value
fstat(2): get file status
fstat64(2): get file status
fstatat(2): get file status
fstatat64(2): get file status
fstatfs(2): get filesystem statistics
fstatfs64(2): get filesystem statistics
fstatvfs(2): get filesystem statistics
fsync(2): synchronize a file's in-core state with storage device
ftruncate(2): truncate a file to a specified length
ftruncate64(2): truncate a file to a specified length
futex(2): fast user-space locking
futimens(2): change file timestamps with nanosecond precision
futimesat(2): change timestamps of a file relative to a directory fi...

G

get_current_dir_name(2): get current working directory
get_kernel_syms(2): retrieve exported kernel and module symbols
get_mempolicy(2): retrieve NUMA memory policy for a thread
get_robust_list(2): get/set list of robust futexes
get_thread_area(2): manipulate thread-local storage information
getcontext(2): get or set the user context
getcpu(2): determine CPU and NUMA node on which the calling threa...
getcwd(2): get current working directory
getdents(2): get directory entries
getdents64(2): get directory entries
getdomainname(2): get/set NIS domain name
getdtablesize(2): get file descriptor table size
getegid(2): get group identity
getegid32(2): get group identity
geteuid(2): get user identity
geteuid32(2): get user identity
getgid(2): get group identity
getgid32(2): get group identity
getgroups(2): get/set list of supplementary group IDs
getgroups32(2): get/set list of supplementary group IDs
gethostid(2): get or set the unique identifier of the current host
gethostname(2): get/set hostname
getitimer(2): get or set value of an interval timer
getmsg(2): unimplemented system calls
getpagesize(2): get memory page size
getpeername(2): get name of connected peer socket
getpgid(2): set/get process group
getpgrp(2): set/get process group
getpid(2): get process identification
getpmsg(2): unimplemented system calls
getppid(2): get process identification
getpriority(2): get/set program scheduling priority
getrandom(2): obtain a series of random bytes
getresgid(2): get real, effective, and saved user/group IDs
getresgid32(2): get real, effective, and saved user/group IDs
getresuid(2): get real, effective, and saved user/group IDs
getresuid32(2): get real, effective, and saved user/group IDs
getrlimit(2): get/set resource limits
getrusage(2): get resource usage
getsid(2): get session ID
getsockname(2): get socket name
getsockopt(2): get and set options on sockets
gettid(2): get thread identification
gettimeofday(2): get / set time
getuid(2): get user identity
getuid32(2): get user identity
getunwind(2): copy the unwind data to caller's buffer
getxattr(2): retrieve an extended attribute value
gtty(2): unimplemented system calls

I

idle(2): make process 0 idle
inb(2): port I/O
inb_p(2): port I/O
init_module(2): load a kernel module
inl(2): port I/O
inl_p(2): port I/O
inotify_add_watch(2): add a watch to an initialized inotify instance
inotify_init(2): initialize an inotify instance
inotify_init1(2): initialize an inotify instance
inotify_rm_watch(2): remove an existing watch from an inotify instance
insb(2): port I/O
insl(2): port I/O
insw(2): port I/O
intro(2): introduction to system calls
inw(2): port I/O
inw_p(2): port I/O
IO::Async::Loop::Poll(3pm): use "IO::Async" with "poll(2)"
IO::Async::Loop::Select(3pm): use IO::Async with "select(2)"
io_cancel(2): cancel an outstanding asynchronous I/O operation
io_destroy(2): destroy an asynchronous I/O context
io_getevents(2): read asynchronous I/O events from the completion queue
io_setup(2): create an asynchronous I/O context
io_submit(2): submit asynchronous I/O blocks for processing
ioctl(2): control device
ioctl_console(2): ioctls for console terminal and virtual consoles
ioctl_fat(2): manipulating the FAT filesystem
ioctl_ficlone(2): share some the data of one file with another file
ioctl_ficlonerange(2): share some the data of one file with another file
ioctl_fideduperange(2): share some the data of one file with another file
ioctl_fslabel(2): get or set a filesystem label
ioctl_getfsmap(2): retrieve the physical layout of the filesystem
ioctl_iflags(2): ioctl() operations for inode flags
ioctl_list(2): list of ioctl calls in Linux/i386 kernel
ioctl_ns(2): ioctl() operations for Linux namespaces
ioctl_tty(2): ioctls for terminals and serial lines
ioctl_userfaultfd(2): create a file descriptor for handling page faults in ...
ioperm(2): set port input/output permissions
iopl(2): change I/O privilege level
ioprio_get(2): get/set I/O scheduling class and priority
ioprio_set(2): get/set I/O scheduling class and priority
ipc(2): System V IPC system calls
isastream(2): unimplemented system calls

K

kcmp(2): compare two processes to determine if they share a ker...
kexec_file_load(2): load a new kernel for later execution
kexec_load(2): load a new kernel for later execution
keyctl(2): manipulate the kernel's key management facility
kill(2): send signal to a process
killpg(2): send signal to a process group
klogctl(2): read and/or clear kernel message ring buffer; set cons...

L

landlock_add_rule(2): add a new Landlock rule to a ruleset
landlock_create_ruleset(2): create a new Landlock ruleset
landlock_restrict_self(2): enforce a Landlock ruleset
lchown(2): change ownership of a file
lchown32(2): change ownership of a file
lgetxattr(2): retrieve an extended attribute value
link(2): make a new name for a file
linkat(2): make a new name for a file
listen(2): listen for connections on a socket
listxattr(2): list extended attribute names
llistxattr(2): list extended attribute names
_llseek(2): reposition read/write file offset
llseek(2): reposition read/write file offset
lock(2): unimplemented system calls
lookup_dcookie(2): return a directory entry's path
lremovexattr(2): remove an extended attribute
lseek(2): reposition read/write file offset
lsetxattr(2): set an extended attribute value
lstat(2): get file status
lstat64(2): get file status

M

madvise(2): give advice about use of memory
madvise1(2): unimplemented system calls
mbind(2): set memory policy for a memory range
membarrier(2): issue memory barriers on a set of threads
memfd_create(2): create an anonymous file
memfd_secret(2): create an anonymous RAM-based file to access secret me...
migrate_pages(2): move all pages in a process to another set of nodes
mincore(2): determine whether pages are resident in memory
mkdir(2): create a directory
mkdirat(2): create a directory
mknod(2): create a special or ordinary file
mknodat(2): create a special or ordinary file
mlock(2): lock and unlock memory
mlock2(2): lock and unlock memory
mlockall(2): lock and unlock memory
mmap(2): map or unmap files or devices into memory
mmap2(2): map files or devices into memory
modify_ldt(2): get or set a per-process LDT entry
mount(2): mount filesystem
mount_setattr(2): change properties of a mount or mount tree
move_pages(2): move individual pages of a process to another node
mprotect(2): set protection on a region of memory
mpx(2): unimplemented system calls
mq_getsetattr(2): get/set message queue attributes
mq_notify(2): register for notification when a message is available
mq_open(2): open a message queue
mq_receive(2): receive a message from a message queue
mq_send(2): send a message to a message queue
mq_timedreceive(2): receive a message from a message queue
mq_timedsend(2): send a message to a message queue
mq_unlink(2): remove a message queue
mremap(2): remap a virtual memory address
msgctl(2): System V message control operations
msgget(2): get a System V message queue identifier
msgop(2): System V message queue operations
msgrcv(2): System V message queue operations
msgsnd(2): System V message queue operations
msync(2): synchronize a file with a memory map
munlock(2): lock and unlock memory
munlockall(2): lock and unlock memory
munmap(2): map or unmap files or devices into memory

N

name_to_handle_at(2): obtain handle for a pathname and open file via a handle
nanosleep(2): high-resolution sleep
newfstatat(2): get file status
_newselect(2): synchronous I/O multiplexing
nfsservctl(2): syscall interface to kernel nfs daemon
nice(2): change process priority
ntp_adjtime(2): tune kernel clock

O

oldfstat(2): get file status
oldlstat(2): get file status
oldolduname(2): get name and information about current kernel
oldstat(2): get file status
olduname(2): get name and information about current kernel
open(2): open and possibly create a file
open_by_handle_at(2): obtain handle for a pathname and open file via a handle
open_how(2type): how to open a pathname
openat(2): open and possibly create a file
openat2(2): open and possibly create a file (extended)
outb(2): port I/O
outb_p(2): port I/O
outl(2): port I/O
outl_p(2): port I/O
outsb(2): port I/O
outsl(2): port I/O
outsw(2): port I/O
outw(2): port I/O
outw_p(2): port I/O

P

pause(2): wait for signal
pciconfig_iobase(2): pci device information handling
pciconfig_read(2): pci device information handling
pciconfig_write(2): pci device information handling
perf_event_open(2): set up performance monitoring
perfmonctl(2): interface to IA-64 performance monitoring unit
personality(2): set the process execution domain
phys(2): unimplemented system calls
pidfd_getfd(2): obtain a duplicate of another process's file descriptor
pidfd_open(2): obtain a file descriptor that refers to a process
pidfd_send_signal(2): send a signal to a process specified by a file descri...
pipe(2): create pipe
pipe2(2): create pipe
pivot_root(2): change the root mount
pkey_alloc(2): allocate or free a protection key
pkey_free(2): allocate or free a protection key
pkey_mprotect(2): set protection on a region of memory
poll(2): wait for some event on a file descriptor
posix_fadvise(2): predeclare an access pattern for file data
ppoll(2): wait for some event on a file descriptor
prctl(2): operations on a process or thread
pread(2): read from or write to a file descriptor at a given offset
pread64(2): read from or write to a file descriptor at a given offset
preadv(2): read or write data into multiple buffers
preadv2(2): read or write data into multiple buffers
prlimit(2): get/set resource limits
prlimit64(2): get/set resource limits
process_madvise(2): give advice about use of memory to a process
process_vm_readv(2): transfer data between process address spaces
process_vm_writev(2): transfer data between process address spaces
prof(2): unimplemented system calls
pselect(2): synchronous I/O multiplexing
pselect6(2): synchronous I/O multiplexing
pthread_atfork(3): register handlers to be called at fork(2) time
ptrace(2): process trace
putmsg(2): unimplemented system calls
putpmsg(2): unimplemented system calls
pwrite(2): read from or write to a file descriptor at a given offset
pwrite64(2): read from or write to a file descriptor at a given offset
pwritev(2): read or write data into multiple buffers
pwritev2(2): read or write data into multiple buffers

Q

query_module(2): query the kernel for various bits pertaining to modules
quotactl(2): manipulate disk quotas

R

read(2): read from a file descriptor
readahead(2): initiate file readahead into page cache
readdir(2): read directory entry
readlink(2): read value of a symbolic link
readlinkat(2): read value of a symbolic link
readv(2): read or write data into multiple buffers
reboot(2): reboot or enable/disable Ctrl-Alt-Del
recv(2): receive a message from a socket
recvfrom(2): receive a message from a socket
recvmmsg(2): receive multiple messages on a socket
recvmsg(2): receive a message from a socket
remap_file_pages(2): create a nonlinear file mapping
removexattr(2): remove an extended attribute
rename(2): change the name or location of a file
renameat(2): change the name or location of a file
renameat2(2): change the name or location of a file
request_key(2): request a key from the kernel's key management facility
restart_syscall(2): restart a system call after interruption by a stop signal
rmdir(2): delete a directory
rt_sigaction(2): examine and change a signal action
rt_sigpending(2): examine pending signals
rt_sigprocmask(2): examine and change blocked signals
rt_sigqueueinfo(2): queue a signal and data
rt_sigreturn(2): return from signal handler and cleanup stack frame
rt_sigsuspend(2): wait for a signal
rt_sigtimedwait(2): synchronously wait for queued signals
rt_tgsigqueueinfo(2): queue a signal and data

S

s390_guarded_storage(2): operations with z/Architecture guarded storage fac...
s390_pci_mmio_read(2): transfer data to/from PCI MMIO memory page
s390_pci_mmio_write(2): transfer data to/from PCI MMIO memory page
s390_runtime_instr(2): enable/disable s390 CPU run-time instrumentation
s390_sthyi(2): emulate STHYI instruction
sbrk(2): change data segment size
sched_get_priority_max(2): get static priority range
sched_get_priority_min(2): get static priority range
sched_getaffinity(2): set and get a thread's CPU affinity mask
sched_getattr(2): set and get scheduling policy and attributes
sched_getparam(2): set and get scheduling parameters
sched_getscheduler(2): set and get scheduling policy/parameters
sched_rr_get_interval(2): get the SCHED_RR interval for the named process
sched_setaffinity(2): set and get a thread's CPU affinity mask
sched_setattr(2): set and get scheduling policy and attributes
sched_setparam(2): set and get scheduling parameters
sched_setscheduler(2): set and get scheduling policy/parameters
sched_yield(2): yield the processor
seccomp(2): operate on Secure Computing state of the process
seccomp_unotify(2): Seccomp user-space notification mechanism
security(2): unimplemented system calls
select(2): synchronous I/O multiplexing
select_tut(2): synchronous I/O multiplexing
semctl(2): System V semaphore control operations
semget(2): get a System V semaphore set identifier
semop(2): System V semaphore operations
semtimedop(2): System V semaphore operations
send(2): send a message on a socket
sendfile(2): transfer data between file descriptors
sendfile64(2): transfer data between file descriptors
sendmmsg(2): send multiple messages on a socket
sendmsg(2): send a message on a socket
sendto(2): send a message on a socket
set_mempolicy(2): set default NUMA memory policy for a thread and its ch...
set_robust_list(2): get/set list of robust futexes
set_thread_area(2): manipulate thread-local storage information
set_tid_address(2): set pointer to thread ID
setcontext(2): get or set the user context
setdomainname(2): get/set NIS domain name
setegid(2): set effective user or group ID
seteuid(2): set effective user or group ID
setfsgid(2): set group identity used for filesystem checks
setfsgid32(2): set group identity used for filesystem checks
setfsuid(2): set user identity used for filesystem checks
setfsuid32(2): set user identity used for filesystem checks
setgid(2): set group identity
setgid32(2): set group identity
setgroups(2): get/set list of supplementary group IDs
setgroups32(2): get/set list of supplementary group IDs
sethostid(2): get or set the unique identifier of the current host
sethostname(2): get/set hostname
setitimer(2): get or set value of an interval timer
setns(2): reassociate thread with a namespace
setpgid(2): set/get process group
setpgrp(2): set/get process group
setpriority(2): get/set program scheduling priority
setregid(2): set real and/or effective user or group ID
setregid32(2): set real and/or effective user or group ID
setresgid(2): set real, effective, and saved user or group ID
setresgid32(2): set real, effective, and saved user or group ID
setresuid(2): set real, effective, and saved user or group ID
setresuid32(2): set real, effective, and saved user or group ID
setreuid(2): set real and/or effective user or group ID
setreuid32(2): set real and/or effective user or group ID
setrlimit(2): get/set resource limits
setsid(2): creates a session and sets the process group ID
setsockopt(2): get and set options on sockets
settimeofday(2): get / set time
setuid(2): set user identity
setuid32(2): set user identity
setup(2): setup devices and filesystems, mount root filesystem
setxattr(2): set an extended attribute value
sgetmask(2): manipulation of signal mask (obsolete)
shmat(2): System V shared memory operations
shmctl(2): System V shared memory control
shmdt(2): System V shared memory operations
shmget(2): allocates a System V shared memory segment
shmop(2): System V shared memory operations
shutdown(2): shut down part of a full-duplex connection
sigaction(2): examine and change a signal action
sigaltstack(2): set and/or get signal stack context
signal(2): ANSI C signal handling
signalfd(2): create a file descriptor for accepting signals
signalfd4(2): create a file descriptor for accepting signals
sigpending(2): examine pending signals
sigprocmask(2): examine and change blocked signals
sigqueue(2): queue a signal and data to a process
sigreturn(2): return from signal handler and cleanup stack frame
sigsuspend(2): wait for a signal
sigtimedwait(2): synchronously wait for queued signals
sigwaitinfo(2): synchronously wait for queued signals
socket(2): create an endpoint for communication
socketcall(2): socket system calls
socketpair(2): create a pair of connected sockets
splice(2): splice data to/from a pipe
spu_create(2): create a new spu context
spu_run(2): execute an SPU context
ssetmask(2): manipulation of signal mask (obsolete)
stat(2): get file status
stat64(2): get file status
statfs(2): get filesystem statistics
statfs64(2): get filesystem statistics
statvfs(2): get filesystem statistics
statx(2): get file status (extended)
stime(2): set time
stty(2): unimplemented system calls
subpage_prot(2): define a subpage protection for an address range
swapoff(2): start/stop swapping to file/device
swapon(2): start/stop swapping to file/device
symlink(2): make a new name for a file
symlinkat(2): make a new name for a file
sync(2): commit filesystem caches to disk
sync_file_range(2): sync a file segment with disk
sync_file_range2(2): sync a file segment with disk
syncfs(2): commit filesystem caches to disk
_syscall(2): invoking a system call without library support (OBSOLETE)
syscall(2): indirect system call
syscalls(2): Linux system calls
_sysctl(2): read/write system parameters
sysctl(2): read/write system parameters
sysfs(2): get filesystem type information
sysinfo(2): return system information
syslog(2): read and/or clear kernel message ring buffer; set cons...

T

tee(2): duplicating pipe content
tgkill(2): send a signal to a thread
time(2): get time in seconds
timer_create(2): create a POSIX per-process timer
timer_delete(2): delete a POSIX per-process timer
timer_getoverrun(2): get overrun count for a POSIX per-process timer
timer_gettime(2): arm/disarm and fetch state of POSIX per-process timer
timer_settime(2): arm/disarm and fetch state of POSIX per-process timer
timerfd_create(2): timers that notify via file descriptors
timerfd_gettime(2): timers that notify via file descriptors
timerfd_settime(2): timers that notify via file descriptors
times(2): get process times
tkill(2): send a signal to a thread
truncate(2): truncate a file to a specified length
truncate64(2): truncate a file to a specified length
tuxcall(2): unimplemented system calls

U

ugetrlimit(2): get/set resource limits
umask(2): set file mode creation mask
umount(2): unmount filesystem
umount2(2): unmount filesystem
uname(2): get name and information about current kernel
unimplemented(2): unimplemented system calls
unlink(2): delete a name and possibly the file it refers to
unlinkat(2): delete a name and possibly the file it refers to
unshare(2): disassociate parts of the process execution context
uselib(2): load shared library
userfaultfd(2): create a file descriptor for handling page faults in u...
ustat(2): get filesystem statistics
utime(2): change file last access and modification times
utimensat(2): change file timestamps with nanosecond precision
utimes(2): change file last access and modification times

V

vfork(2): create a child process and block parent
vhangup(2): virtually hangup the current terminal
vm86(2): enter virtual 8086 mode
vm86old(2): enter virtual 8086 mode
vmsplice(2): splice user pages to/from a pipe
vserver(2): unimplemented system calls

W

wait(2): wait for process to change state
wait3(2): wait for process to change state, BSD style
wait4(2): wait for process to change state, BSD style
waitid(2): wait for process to change state
waitpid(2): wait for process to change state
write(2): write to a file descriptor
writev(2): read or write data into multiple buffers

X

xfce4-popup-places(22): quick access to folders, documents and removable media

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