man2/syscalls.2

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  31 .TH SYSCALLS 2 2013-02-10 "Linux" "Linux Programmer's Manual"
  32 .SH NAME
  33 syscalls \- Linux system calls
  34 .SH SYNOPSIS
  35 Linux system calls.
  36 .SH DESCRIPTION
  37 The system call is the fundamental interface between an application
  38 and the Linux kernel.
  39 .SS System calls and library wrapper functions
  40 System calls are generally not invoked directly,
  41 but rather via wrapper functions in glibc (or perhaps some other library).
  42 For details of direct invocation of a system call, see
  43 .BR intro (2).
  44 Often, but not always, the name of the wrapper function is the same
  45 as the name of the system call that it invokes.
  46 For example, glibc contains a function
  47 .BR truncate ()
  48 which invokes the underlying "truncate" system call.
  49
  50 Often the glibc wrapper function is quite thin, doing little work
  51 other than copying arguments to the right registers
  52 before invoking the system call,
  53 and then setting
  54 .I errno
  55 appropriately after the system call has returned.
  56 (These are the same steps that are performed by
  57 .BR syscall (2),
  58 which can be used to invoke system calls
  59 for which no wrapper function is provided.)
  60 Note: system calls indicate a failure by returning a negative error
  61 number to the caller;
  62 when this happens,
  63 the wrapper function negates the returned error number
  64 (to make it positive), copies it to
  65 .IR errno ,
  66 and returns \-1 to the caller of the wrapper.
  67
  68 Sometimes, however, the wrapper function does some extra work
  69 before invoking the system call.
  70 For example, nowadays there are (for reasons described below) two
  71 related system calls,
  72 .BR truncate (2)
  73 and
  74 .BR truncate64 (2),
  75 and the glibc
  76 .BR truncate ()
  77 wrapper function checks which of those system calls
  78 are provided by the kernel and determines which should be employed.
  79 .SS System call list
  80 Below is a list of the Linux system calls.
  81 In the list, the
  82 .I Kernel
  83 column indicates the kernel version
  84 for those system calls that were new in Linux 2.2,
  85 or have appeared since that kernel version.
  86 Note the following points:
  87 .IP * 3
  88 Where no kernel version is indicated,
  89 the system call appeared in kernel 1.0 or earlier.
  90 .IP *
  91 Where a system call is marked "1.2"
  92 this means the system call probably appeared in a 1.1.x kernel version,
  93 and first appeared in a stable kernel with 1.2.
  94 (Development of the 1.2 kernel was initiated from a branch of kernel
  95 1.0.6 via the 1.1.x unstable kernel series.)
  96 .IP *
  97 Where a system call is marked "2.0"
  98 this means the system call probably appeared in a 1.3.x kernel version,
  99 and first appeared in a stable kernel with 2.0.
 100 (Development of the 2.0 kernel was initiated from a branch of kernel
 101 1.2.x, somewhere around 1.2.10,
 102 via the 1.3.x unstable kernel series.)
 103 .\" Was kernel 2.0 started from a branch of 1.2.10?
 104 .\" At least from the timestamps of the tarballs of
 105 .\" of 1.2.10 and 1.3.0, that's how it looks, but in
 106 .\" fact the diff doesn't seem very clear, the
 107 .\" 1.3.0 .tar.bz is much bigger (2.0 MB) than the
 108 .\" 1.2.10 .tar.bz2 (1.8 MB), and AEB points out the
 109 .\" timestamps of some files in 1.3.0 seem to be older
 110 .\" than those in 1.2.10.  All of this suggests
 111 .\" that there might not have been a clean branch point.
 112 .IP *
 113 Where a system call is marked "2.2"
 114 this means the system call probably appeared in a 2.1.x kernel version,
 115 and first appeared in a stable kernel with 2.2.0.
 116 (Development of the 2.2 kernel was initiated from a branch of kernel
 117 2.0.21 via the 2.1.x unstable kernel series.)
 118 .IP *
 119 Where a system call is marked "2.4"
 120 this means the system call probably appeared in a 2.3.x kernel version,
 121 and first appeared in a stable kernel with 2.4.0.
 122 (Development of the 2.4 kernel was initiated from a branch of
 123 kernel 2.2.8 via the 2.3.x unstable kernel series.)
 124 .IP *
 125 Where a system call is marked "2.6"
 126 this means the system call probably appeared in a 2.5.x kernel version,
 127 and first appeared in a stable kernel with 2.6.0.
 128 (Development of kernel 2.6 was initiated from a branch
 129 of kernel 2.4.15 via the 2.5.x unstable kernel series.)
 130 .IP *
 131 Starting with kernel 2.6.0, the development model changed,
 132 and new system calls may appear in each 2.6.x release.
 133 In this case, the exact version number where the system call appeared
 134 is shown.
 135 This convention continues with the 3.x kernel series,
 136 which followed on from kernel 2.6.39.
 137 .IP *
 138 In some cases, a system call was added to a stable kernel
 139 series after it branched from the previous stable kernel
 140 series, and then backported into the earlier stable kernel series.
 141 For example some system calls that appeared in 2.6.x were also backported
 142 into a 2.4.x release after 2.4.15.
 143 When this is so, the version where the system call appeared
 144 in both of the major kernel series is listed.
 145 .PP
 146 The list of system calls that are available as at kernel 3.5
 147 (or in a few cases only on older kernels) is as follows:
 148 .\"
 149 .\" Looking at scripts/checksyscalls.sh in the kernel source is
 150 .\" instructive about x86 specifics.
 151 .\"
 152 .ad l
 153 .TS
 154 l l l
 155 ---
 156 l l l.
 157 \fBSystem call\fP       \fBKernel\fP    \fBNotes\fP
 158
 159 \fB_llseek\fP(2)        1.2
 160 \fB_newselect\fP(2)
 161 \fB_sysctl\fP(2)
 162 \fBaccept\fP(2)
 163 \fBaccept4\fP(2)        2.6.28
 164 \fBaccess\fP(2)
 165 \fBacct\fP(2)
 166 \fBadd_key\fP(2)        2.6.11
 167 \fBadjtimex\fP(2)
 168 \fBalarm\fP(2)
 169 \fBalloc_hugepages\fP(2)        2.5.36  Removed in 2.5.44
 170 \fBbdflush\fP(2)                T{
 171 Deprecated (does nothing) since 2.6
 172 T}
 173 \fBbind\fP(2)
 174 \fBbrk\fP(2)
 175 \fBcacheflush\fP(2)     1.2     Not on x86
 176 \fBcapget\fP(2) 2.2
 177 \fBcapset\fP(2) 2.2
 178 \fBchdir\fP(2)
 179 \fBchmod\fP(2)
 180 \fBchown\fP(2)
 181 \fBchown32\fP(2)        2.4
 182 \fBchroot\fP(2)
 183 \fBclock_adjtime\fP(2)  2.6.39
 184 \fBclock_getres\fP(2)   2.6
 185 \fBclock_gettime\fP(2)  2.6
 186 \fBclock_nanosleep\fP(2)        2.6
 187 \fBclock_settime\fP(2)  2.6
 188 \fBclone\fP(2)
 189 \fBclose\fP(2)
 190 \fBconnect\fP(2)
 191 \fBcreat\fP(2)
 192 \fBcreate_module\fP(2)          Removed in 2.6
 193 \fBdelete_module\fP(2)
 194 \fBdup\fP(2)
 195 \fBdup2\fP(2)
 196 \fBdup3\fP(2)   2.6.27
 197 \fBepoll_create\fP(2)   2.6
 198 \fBepoll_create1\fP(2)  2.6.27
 199 \fBepoll_ctl\fP(2)      2.6
 200 \fBepoll_pwait\fP(2)    2.6.19
 201 \fBepoll_wait\fP(2)     2.6
 202 \fBeventfd\fP(2)        2.6.22
 203 \fBeventfd2\fP(2)       2.6.27
 204 \fBexecve\fP(2)
 205 \fBexit\fP(2)
 206 \fBexit_group\fP(2)     2.6
 207 \fBfaccessat\fP(2)      2.6.16
 208 \fBfadvise64\fP(2)      2.6
 209 .\" Implements \fBposix_fadvise\fP(2)
 210 \fBfadvise64_64\fP(2)   2.6
 211 \fBfallocate\fP(2)      2.6.23
 212 \fBfanotify_init\fP(2)  2.6.37
 213 \fBfanotify_mark\fP(2)  2.6.37
 214 .\" The fanotify calls were added in Linux 2.6.36,
 215 .\" but disabled while the API was finalized.
 216 \fBfchdir\fP(2)
 217 \fBfchmod\fP(2)
 218 \fBfchmodat\fP(2)       2.6.16
 219 \fBfchown\fP(2)
 220 \fBfchown32\fP(2)       2.4
 221 \fBfchownat\fP(2)       2.6.16
 222 \fBfcntl\fP(2)
 223 \fBfcntl64\fP(2)        2.4
 224 \fBfdatasync\fP(2)
 225 \fBfgetxattr\fP(2)      2.6; 2.4.18
 226 \fBfinit_module\fP(2)   3.8
 227 \fBflistxattr\fP(2)     2.6; 2.4.18
 228 \fBflock\fP(2)  2.0
 229 \fBfork\fP(2)
 230 \fBfree_hugepages\fP(2) 2.5.36  Removed in 2.5.44
 231 \fBfremovexattr\fP(2)   2.6; 2.4.18
 232 \fBfsetxattr\fP(2)      2.6; 2.4.18
 233 \fBfstat\fP(2)
 234 \fBfstat64\fP(2)        2.4
 235 \fBfstatat64\fP(2)      2.6.16
 236 \fBfstatfs\fP(2)
 237 \fBfstatfs64\fP(2)      2.6
 238 \fBfsync\fP(2)
 239 \fBftruncate\fP(2)
 240 \fBftruncate64\fP(2)    2.4
 241 \fBfutex\fP(2)  2.6
 242 \fBfutimesat\fP(2)      2.6.16
 243 \fBget_kernel_syms\fP(2)                Removed in 2.6
 244 \fBget_mempolicy\fP(2)  2.6.6
 245 \fBget_robust_list\fP(2)        2.6.17
 246 \fBget_thread_area\fP(2)        2.6
 247 \fBgetcpu\fP(2) 2.6.19
 248 \fBgetcwd\fP(2) 2.2
 249 \fBgetdents\fP(2)       2.0
 250 \fBgetdents64\fP(2)     2.4
 251 \fBgetegid\fP(2)
 252 \fBgetegid32\fP(2)      2.4
 253 \fBgeteuid\fP(2)
 254 \fBgeteuid32\fP(2)      2.4
 255 \fBgetgid\fP(2)
 256 \fBgetgid32\fP(2)       2.4
 257 \fBgetgroups\fP(2)
 258 \fBgetgroups32\fP(2)    2.4
 259 \fBgetitimer\fP(2)
 260 \fBgetpeername\fP(2)
 261 \fBgetpagesize\fP(2)    2.0     Not on x86
 262 \fBgetpgid\fP(2)
 263 \fBgetpgrp\fP(2)
 264 \fBgetpid\fP(2)
 265 \fBgetppid\fP(2)
 266 \fBgetpriority\fP(2)
 267 \fBgetresgid\fP(2)      2.2
 268 \fBgetresgid32\fP(2)    2.4
 269 \fBgetresuid\fP(2)      2.2
 270 \fBgetresuid32\fP(2)    2.4
 271 \fBgetrlimit\fP(2)
 272 \fBgetrusage\fP(2)
 273 \fBgetsid\fP(2) 2.0
 274 \fBgetsockname\fP(2)
 275 \fBgetsockopt\fP(2)
 276 \fBgettid\fP(2) 2.4.11
 277 \fBgettimeofday\fP(2)
 278 \fBgetuid\fP(2)
 279 \fBgetuid32\fP(2)       2.4
 280 .\" \fBgetunwind\fP(2)  2.4.8   ia64; DEPRECATED
 281 \fBgetxattr\fP(2)       2.6; 2.4.18
 282 \fBinit_module\fP(2)
 283 \fBinotify_add_watch\fP(2)      2.6.13
 284 \fBinotify_init\fP(2)   2.6.13
 285 \fBinotify_init1\fP(2)  2.6.27
 286 \fBinotify_rm_watch\fP(2)       2.6.13
 287 \fBio_cancel\fP(2)      2.6
 288 \fBio_destroy\fP(2)     2.6
 289 \fBio_getevents\fP(2)   2.6
 290 \fBio_setup\fP(2)       2.6
 291 \fBio_submit\fP(2)      2.6
 292 \fBioctl\fP(2)
 293 \fBioperm\fP(2)
 294 \fBiopl\fP(2)
 295 \fBioprio_get\fP(2)     2.6.13
 296 \fBioprio_set\fP(2)     2.6.13
 297 \fBipc\fP(2)
 298 .\" Implements System V IPC calls
 299 \fBkcmp\fP(2)   3.5
 300 \fBkern_features\fP(2)  3.7     Sparc64
 301 \fBkexec_load\fP(2)     2.6.13
 302 .\" The entry in the syscall table was reserved starting in 2.6.7
 303 .\" Was named sys_kexec_load() from 2.6.7 to 2.6.16
 304 \fBkeyctl\fP(2) 2.6.11
 305 \fBkill\fP(2)
 306 \fBlchown\fP(2) 2.2
 307 \fBlchown32\fP(2)       2.4
 308 \fBlgetxattr\fP(2)      2.6; 2.4.18
 309 \fBlink\fP(2)
 310 \fBlinkat\fP(2) 2.6.16
 311 \fBlisten\fP(2)
 312 \fBlistxattr\fP(2)      2.6; 2.4.18
 313 \fBllistxattr\fP(2)     2.6; 2.4.18
 314 \fBlookup_dcookie\fP(2) 2.6
 315 \fBlremovexattr\fP(2)   2.6; 2.4.18
 316 \fBlseek\fP(2)
 317 \fBlsetxattr\fP(2)      2.6; 2.4.18
 318 \fBlstat\fP(2)
 319 \fBlstat64\fP(2)        2.4
 320 \fBmadvise\fP(2)        2.4
 321 \fBmadvise1\fP(2)       2.4
 322 \fBmbind\fP(2)  2.6.6
 323 .\" \fBmemory_ordering\fP(2)    ???     Sparc64
 324 \fBmigrate_pages\fP(2)  2.6.16
 325 \fBmincore\fP(2)        2.4
 326 \fBmkdir\fP(2)
 327 \fBmkdirat\fP(2)        2.6.16
 328 \fBmknod\fP(2)
 329 \fBmknodat\fP(2)        2.6.16
 330 \fBmlock\fP(2)
 331 \fBmlockall\fP(2)
 332 \fBmmap\fP(2)
 333 \fBmmap2\fP(2)  2.4
 334 \fBmodify_ldt\fP(2)
 335 \fBmount\fP(2)
 336 \fBmove_pages\fP(2)     2.6.18
 337 \fBmprotect\fP(2)
 338 \fBmq_getsetattr\fP(2)  2.6.6
 339 .\" Implements \fBmq_getattr\fP(3) and \fBmq_setattr\fP(3)
 340 \fBmq_notify\fP(2)      2.6.6
 341 \fBmq_open\fP(2)        2.6.6
 342 \fBmq_timedreceive\fP(2)        2.6.6
 343 \fBmq_timedsend\fP(2)   2.6.6
 344 \fBmq_unlink\fP(2)
 345 \fBmremap\fP(2) 2.0
 346 \fBmsgctl\fP(2)
 347 \fBmsgget\fP(2)
 348 \fBmsgrcv\fP(2)
 349 \fBmsgsnd\fP(2)
 350 \fBmsync\fP(2)  2.0
 351 .\" \fBmultiplexer\fP(2)        ??      __NR_multiplexer reserved on
 352 .\"             PowerPC, but unimplemented?
 353 \fBmunlock\fP(2)
 354 \fBmunlockall\fP(2)
 355 \fBmunmap\fP(2)
 356 \fBname_to_handle_at\fP(2)      2.6.39
 357 \fBnanosleep\fP(2)      2.0
 358 \fBnfsservctl\fP(2)     2.2     Removed in 3.1
 359 \fBnice\fP(2)
 360 \fBoldfstat\fP(2)
 361 \fBoldlstat\fP(2)
 362 \fBoldolduname\fP(2)
 363 \fBoldstat\fP(2)
 364 \fBolduname\fP(2)
 365 \fBopen\fP(2)
 366 \fBopen_by_handle_at\fP(2)      2.6.39
 367 \fBopenat\fP(2) 2.6.16
 368 \fBpause\fP(2)
 369 \fBpciconfig_iobase\fP(2)       2.2.15; 2.4     Not on x86
 370 .\" Alpha, PowerPC, ARM; not x86
 371 \fBpciconfig_read\fP(2) 2.0.26; 2.2     Not on x86
 372 .\" , PowerPC, ARM; not x86
 373 \fBpciconfig_write\fP(2)        2.0.26; 2.2     Not on x86
 374 .\" , PowerPC, ARM; not x86
 375 \fBperf_event_open\fP(2)        2.6.31  T{
 376 Was called perf_counter_open() in 2.6.31; renamed in 2.6.32
 377 T}
 378 \fBpersonality\fP(2)    1.2
 379 \fBperfctr\fP(2)        2.2     Sparc; removed in 2.6.34
 380 .\"     commit c7d5a0050773e98d1094eaa9f2a1a793fafac300 removed perfctr()
 381 .\" \fBperfmonctl\fP(2) ???     ia64
 382 \fBpipe\fP(2)
 383 \fBpipe2\fP(2)  2.6.27
 384 \fBpivot_root\fP(2)     2.4
 385 \fBpoll\fP(2)   2.2
 386 \fBppc_rtas\fP(2)               PowerPC only
 387 \fBppoll\fP(2)  2.6.16
 388 \fBprctl\fP(2)  2.2
 389 \fBpread64\fP(2)                T{
 390 Added as "pread" in 2.2; renamed "pread64" in 2.6
 391 T}
 392 \fBpreadv\fP(2) 2.6.30
 393 \fBprlimit\fP(2)        2.6.36
 394 \fBprocess_vm_readv\fP(2)       3.2
 395 \fBprocess_vm_writev\fP(2)      3.2
 396 \fBpselect6\fP(2)       2.6.16
 397 .\" Implements \fBpselect\fP(2)
 398 \fBptrace\fP(2)
 399 \fBpwrite64\fP(2)               T{
 400 Added as "pwrite" in 2.2; renamed "pwrite64" in 2.6
 401 T}
 402 \fBpwritev\fP(2)        2.6.30
 403 \fBquery_module\fP(2)   2.2     Removed in 2.6
 404 \fBquotactl\fP(2)
 405 \fBread\fP(2)
 406 \fBreadahead\fP(2)      2.4.13
 407 \fBreaddir\fP(2)
 408 .\" Supersedes \fBgetdents\fP(2)
 409 \fBreadlink\fP(2)
 410 \fBreadlinkat\fP(2)     2.6.16
 411 \fBreadv\fP(2)  2.0
 412 \fBreboot\fP(2)
 413 \fBrecv\fP(2)
 414 \fBrecvfrom\fP(2)
 415 \fBrecvmsg\fP(2)
 416 \fBrecvmmsg\fP(2)       2.6.33
 417 \fBremap_file_pages\fP(2)       2.6
 418 \fBremovexattr\fP(2)    2.6; 2.4.18
 419 \fBrename\fP(2)
 420 \fBrenameat\fP(2)       2.6.16
 421 \fBrequest_key\fP(2)    2.6.11
 422 \fBrestart_syscall\fP(2)        2.6
 423 \fBrmdir\fP(2)
 424 \fBrt_sigaction\fP(2)   2.2
 425 \fBrt_sigpending\fP(2)  2.2
 426 \fBrt_sigprocmask\fP(2) 2.2
 427 \fBrt_sigqueueinfo\fP(2)        2.2
 428 \fBrt_sigreturn\fP(2)   2.2
 429 \fBrt_sigsuspend\fP(2)  2.2
 430 \fBrt_sigtimedwait\fP(2)        2.2
 431 \fBrt_tgsigqueueinfo\fP(2)      2.6.31
 432 \fBs390_runtime_instr\fP(2)     3.7     s390 only
 433 \fBsched_get_priority_max\fP(2) 2.0
 434 \fBsched_get_priority_min\fP(2) 2.0
 435 \fBsched_getaffinity\fP(2)      2.6
 436 \fBsched_getparam\fP(2) 2.0
 437 \fBsched_getscheduler\fP(2)     2.0
 438 \fBsched_rr_get_interval\fP(2)  2.0
 439 \fBsched_setaffinity\fP(2)      2.6
 440 \fBsched_setparam\fP(2) 2.0
 441 \fBsched_setscheduler\fP(2)     2.0
 442 \fBsched_yield\fP(2)    2.0
 443 \fBselect\fP(2)
 444 \fBsemctl\fP(2)
 445 \fBsemget\fP(2)
 446 \fBsemop\fP(2)
 447 \fBsemtimedop\fP(2)     2.6; 2.4.22
 448 \fBsend\fP(2)
 449 \fBsendfile\fP(2)       2.2
 450 \fBsendfile64\fP(2)     2.6; 2.4.19
 451 \fBsendmmsg\fP(2)       3.0
 452 \fBsendmsg\fP(2)
 453 \fBsendto\fP(2)
 454 \fBset_mempolicy\fP(2)  2.6.6
 455 \fBset_robust_list\fP(2)        2.6.17
 456 \fBset_thread_area\fP(2)        2.6
 457 \fBset_tid_address\fP(2)        2.6
 458 .\" See http://lkml.org/lkml/2005/8/1/83
 459 .\" "[PATCH] remove sys_set_zone_reclaim()"
 460 \fBsetdomainname\fP(2)
 461 \fBsetfsgid\fP(2)       1.2
 462 \fBsetfsgid32\fP(2)     2.4
 463 \fBsetfsuid\fP(2)       1.2
 464 \fBsetfsuid32\fP(2)     2.4
 465 \fBsetgid\fP(2)
 466 \fBsetgid32\fP(2)       2.4
 467 \fBsetgroups\fP(2)
 468 \fBsetgroups32\fP(2)    2.4
 469 \fBsethostname\fP(2)
 470 \fBsetitimer\fP(2)
 471 \fBsetns\fP(2)  3.0
 472 \fBsetpgid\fP(2)
 473 \fBsetpriority\fP(2)
 474 \fBsetregid\fP(2)
 475 \fBsetregid32\fP(2)     2.4
 476 \fBsetresgid\fP(2)      2.2
 477 \fBsetresgid32\fP(2)    2.4
 478 \fBsetresuid\fP(2)      2.2
 479 \fBsetresuid32\fP(2)    2.4
 480 \fBsetreuid\fP(2)
 481 \fBsetreuid32\fP(2)     2.4
 482 \fBsetrlimit\fP(2)
 483 \fBsetsid\fP(2)
 484 \fBsetsockopt\fP(2)
 485 \fBsettimeofday\fP(2)
 486 \fBsetuid\fP(2)
 487 \fBsetuid32\fP(2)       2.4
 488 \fBsetup\fP(2)          Removed in 2.2
 489 \fBsetxattr\fP(2)       2.6; 2.4.18
 490 \fBsgetmask\fP(2)
 491 \fBshmat\fP(2)
 492 \fBshmctl\fP(2)
 493 \fBshmdt\fP(2)
 494 \fBshmget\fP(2)
 495 \fBshutdown\fP(2)
 496 \fBsigaction\fP(2)
 497 \fBsigaltstack\fP(2)    2.2
 498 \fBsignal\fP(2)
 499 \fBsignalfd\fP(2)       2.6.22
 500 \fBsignalfd4\fP(2)      2.6.27
 501 \fBsigpending\fP(2)
 502 \fBsigprocmask\fP(2)
 503 \fBsigreturn\fP(2)
 504 \fBsigsuspend\fP(2)
 505 \fBsocket\fP(2)
 506 \fBsocketcall\fP(2)
 507 .\" Implements BSD socket calls
 508 \fBsocketpair\fP(2)
 509 \fBsplice\fP(2) 2.6.17
 510 \fBspu_create\fP(2)     2.6.16  PowerPC only
 511 \fBspu_run\fP(2)        2.6.16  PowerPC only
 512 \fBssetmask\fP(2)
 513 \fBstat\fP(2)
 514 \fBstat64\fP(2) 2.4
 515 \fBstatfs\fP(2)
 516 \fBstatfs64\fP(2)       2.6
 517 \fBstime\fP(2)
 518 \fBsubpage_prot\fP(2)   2.6.25  PowerPC if
 519                 CONFIG_PPC_64K_PAGES
 520 \fBswapoff\fP(2)
 521 \fBswapon\fP(2)
 522 \fBsymlink\fP(2)
 523 \fBsymlinkat\fP(2)      2.6.16
 524 \fBsync\fP(2)
 525 \fBsync_file_range\fP(2)        2.6.17
 526 \fBsync_file_range2\fP(2)       2.6.22  T{
 527 Architecture-specific variant of \fBsync_file_range\fP(2)
 528 T}
 529 .\" PowerPC, ARM, tile
 530 .\" First appeared on ARM, as arm_sync_file_range(), but later renamed
 531 .\" \fBsys_debug_setcontext\fP(2)       ???     PowerPC if CONFIG_PPC32
 532 \fBsyncfs\fP(2) 2.6.39
 533 \fBsysfs\fP(2)  1.2
 534 \fBsysinfo\fP(2)
 535 \fBsyslog\fP(2)
 536 .\" glibc interface is \fBklogctl\fP(3)
 537 \fBtee\fP(2)    2.6.17
 538 \fBtgkill\fP(2) 2.6
 539 \fBtime\fP(2)
 540 \fBtimer_create\fP(2)   2.6
 541 \fBtimer_delete\fP(2)   2.6
 542 \fBtimer_getoverrun\fP(2)       2.6
 543 \fBtimer_gettime\fP(2)  2.6
 544 \fBtimer_settime\fP(2)  2.6
 545 \fBtimerfd_create\fP(2) 2.6.25
 546 \fBtimerfd_gettime\fP(2)        2.6.25
 547 \fBtimerfd_settime\fP(2)        2.6.25
 548 \fBtimes\fP(2)
 549 \fBtkill\fP(2)  2.6; 2.4.22
 550 \fBtruncate\fP(2)
 551 \fBtruncate64\fP(2)     2.4
 552 \fBugetrlimit\fP(2)     2.4
 553 \fBumask\fP(2)
 554 \fBumount\fP(2)
 555 .\" sys_oldumount() -- __NR_umount
 556 \fBumount2\fP(2)        2.2
 557 .\" sys_umount() -- __NR_umount2
 558 \fBuname\fP(2)
 559 \fBunlink\fP(2)
 560 \fBunlinkat\fP(2)       2.6.16
 561 \fBunshare\fP(2)        2.6.16
 562 \fBuselib\fP(2)
 563 \fBustat\fP(2)
 564 \fButime\fP(2)
 565 \fButimensat\fP(2)      2.6.22
 566 \fButimes\fP(2) 2.2
 567 \fButrap_install\fP(2)  2.2     Sparc
 568 \fBvfork\fP(2)
 569 \fBvhangup\fP(2)
 570 \fBvm86old\fP(2)
 571 .\" Superseded by \fBvm86\fP(2)
 572 \fBvmsplice\fP(2)       2.6.17
 573 \fBwait4\fP(2)
 574 \fBwaitid\fP(2) 2.6.10
 575 \fBwaitpid\fP(2)
 576 \fBwrite\fP(2)
 577 \fBwritev\fP(2) 2.0
 578 .TE
 579 .ad
 580 .PP
 581 On many platforms, including x86-32, socket calls are all multiplexed
 582 (via glibc wrapper functions) through
 583 .BR socketcall (2)
 584 and similarly System V IPC calls are multiplexed through
 585 .BR ipc (2).
 586
 587 Although slots are reserved for them in the system call table,
 588 the following system calls are not implemented in the standard kernel:
 589 .BR afs_syscall (2), \" __NR_afs_syscall is 53 on Linux 2.6.22/i386
 590 .BR break (2),       \" __NR_break is 17 on Linux 2.6.22/i386
 591 .BR ftime (2),       \" __NR_ftime is 35 on Linux 2.6.22/i386
 592 .BR getpmsg (2),     \" __NR_getpmsg is 188 on Linux 2.6.22/i386
 593 .BR gtty (2),        \" __NR_gtty is 32 on Linux 2.6.22/i386
 594 .BR idle (2),        \" __NR_idle is 112 on Linux 2.6.22/i386
 595 .BR lock (2),        \" __NR_lock is 53 on Linux 2.6.22/i386
 596 .BR madvise1 (2),    \" __NR_madvise1 is 219 on Linux 2.6.22/i386
 597 .BR mpx (2),         \" __NR_mpx is 66 on Linux 2.6.22/i386
 598 .BR phys (2),        \" Slot has been reused
 599 .BR prof (2),        \" __NR_prof is 44 on Linux 2.6.22/i386
 600 .BR profil (2),      \" __NR_profil is 98 on Linux 2.6.22/i386
 601 .BR putpmsg (2),     \" __NR_putpmsg is 189 on Linux 2.6.22/i386
 602 .\" __NR_security is 223 on Linux 2.4/i386; absent on 2.6/i386, present
 603 .\" on a couple of 2.6 architectures
 604 .BR security (2),    \" __NR_security is 223 on Linux 2.4/i386
 605 .\" The security call is for future use.
 606 .BR stty (2),        \" __NR_stty is 31 on Linux 2.6.22/i386
 607 .BR tuxcall (2),     \" __NR_tuxcall is 184 on x86_64, also on PPC and alpha
 608 .BR ulimit (2),      \" __NR_ulimit is 58 on Linux 2.6.22/i386
 609 and
 610 .BR vserver (2)      \" __NR_vserver is 273 on Linux 2.6.22/i386
 611 (see also
 612 .BR unimplemented (2)).
 613 However,
 614 .BR ftime (3),
 615 .BR profil (3)
 616 and
 617 .BR ulimit (3)
 618 exist as library routines.
 619 The slot for
 620 .BR phys (2)
 621 is in use since kernel 2.1.116 for
 622 .BR umount (2);
 623 .BR phys (2)
 624 will never be implemented.
 625 The
 626 .BR getpmsg (2)
 627 and
 628 .BR putpmsg (2)
 629 calls are for kernels patched to support STREAMS,
 630 and may never be in the standard kernel.
 631
 632 There was briefly
 633 .BR set_zone_reclaim (2),
 634 added in Linux 2.6.13, and removed in 2.6.16;
 635 this system call was never available to user space.
 636 .SH NOTES
 637 .PP
 638 Roughly speaking, the code belonging to the system call
 639 with number __NR_xxx defined in
 640 .I /usr/include/asm/unistd.h
 641 can be found in the Linux kernel source in the routine
 642 .IR sys_xxx ().
 643 (The dispatch table for i386 can be found in
 644 .IR /usr/src/linux/arch/i386/kernel/entry.S .)
 645 There are many exceptions, however, mostly because
 646 older system calls were superseded by newer ones,
 647 and this has been treated somewhat unsystematically.
 648 On platforms with
 649 proprietary operating-system emulation,
 650 such as parisc, sparc, sparc64 and alpha,
 651 there are many additional system calls; mips64 also contains a full
 652 set of 32-bit system calls.
 653
 654 Over time, changes to the interfaces of some system calls have been
 655 necessary.
 656 One reason for such changes was the need to increase the size of
 657 structures or scalar values passed to the system call.
 658 Because of these changes, there are now various groups
 659 of related system calls
 660 (e.g.,
 661 .BR truncate (2)
 662 and
 663 .BR truncate64 (2))
 664 which perform similar tasks, but which vary in
 665 details such as the size of their arguments.
 666 (As noted earlier, applications are generally unaware of this:
 667 the glibc wrapper functions do some work to ensure that the right
 668 system call is invoked, and that ABI compatibility is
 669 preserved for old binaries.)
 670 Examples of systems calls that exist in multiple versions are
 671 the following:
 672 .IP * 3
 673 By now there are three different versions of
 674 .BR stat (2):
 675 .IR sys_stat ()
 676 (slot
 677 .IR __NR_oldstat ),
 678 .IR sys_newstat ()
 679 (slot
 680 .IR __NR_stat ),
 681 and
 682 .IR sys_stat64 ()
 683 (slot
 684 .IR __NR_stat64 ),
 685 with the last being the most current.
 686 .\" e.g., on 2.6.22/i386: __NR_oldstat 18, __NR_stat 106, __NR_stat64 195
 687 .\" The stat system calls deal with three different data structures,
 688 .\" defined in include/asm-i386/stat.h: __old_kernel_stat, stat, stat64
 689 A similar story applies for
 690 .BR lstat (2)
 691 and
 692 .BR fstat (2).
 693 .IP *
 694 Similarly, the defines
 695 .IR __NR_oldolduname ,
 696 .IR __NR_olduname ,
 697 and
 698 .I __NR_uname
 699 refer to the routines
 700 .IR sys_olduname (),
 701 .IR sys_uname ()
 702 and
 703 .IR sys_newuname ().
 704 .IP *
 705 In Linux 2.0, a new version of
 706 .BR vm86 (2)
 707 appeared, with the old and the new kernel routines being named
 708 .IR sys_vm86old ()
 709 and
 710 .IR sys_vm86 ().
 711 .IP *
 712 In Linux 2.4, a new version of
 713 .BR getrlimit (2)
 714 appeared, with the old and the new kernel routines being named
 715 .IR sys_old_getrlimit ()
 716 (slot
 717 .IR __NR_getrlimit )
 718 and
 719 .IR sys_getrlimit ()
 720 (slot
 721 .IR __NR_ugetrlimit ).
 722 .IP *
 723 Linux 2.4 increased the size of user and group IDs from 16 to 32 bits.
 724 .\" 64-bit off_t changes: ftruncate64, *stat64,
 725 .\" fcntl64 (because of the flock structure), getdents64, *statfs64
 726 To support this change, a range of system calls were added
 727 (e.g.,
 728 .BR chown32 (2),
 729 .BR getuid32 (2),
 730 .BR getgroups32 (2),
 731 .BR setresuid32 (2)),
 732 superseding earlier calls of the same name without the
 733 "32" suffix.
 734 .IP *
 735 Linux 2.4 added support for applications on 32-bit architectures
 736 to access large files (i.e., files for which the sizes and
 737 file offsets can't be represented in 32 bits.)
 738 To support this change, replacements were required for system calls
 739 that deal with file offsets and sizes.
 740 Thus the following system calls were added:
 741 .BR fcntl64 (2),
 742 .BR ftruncate64 (2),
 743 .BR getdents64 (2),
 744 .BR stat64 (2),
 745 .BR statfs64 (2),
 746 and their analogs that work with file descriptors or
 747 symbolic links.
 748 These system calls supersede the older system calls
 749 which, except in the case of the "stat" calls,
 750 have the same name without the "64" suffix.
 751
 752 On newer platforms that only have 64-bit file access and 32-bit uids
 753 (e.g., alpha, ia64, s390x) there are no *64 or *32 calls.
 754 Where the *64 and *32 calls exist, the other versions are obsolete.
 755 .IP *
 756 The
 757 .I rt_sig*
 758 calls were added in kernel 2.2 to support the addition
 759 of real-time signals (see
 760 .BR signal (7)).
 761 These system calls supersede the older system calls of the same
 762 name without the "rt_" prefix.
 763 .IP *
 764 The
 765 .BR select (2)
 766 and
 767 .BR mmap (2)
 768 system calls use five or more arguments,
 769 which caused problems in the way
 770 argument passing on the i386 used to be set up.
 771 Thus, while other architectures have
 772 .IR sys_select ()
 773 and
 774 .IR sys_mmap ()
 775 corresponding to
 776 .I __NR_select
 777 and
 778 .IR __NR_mmap ,
 779 on i386 one finds
 780 .IR old_select ()
 781 and
 782 .IR old_mmap ()
 783 (routines that use a pointer to a
 784 argument block) instead.
 785 These days passing five arguments
 786 is not a problem any more, and there is a
 787 .I __NR__newselect
 788 .\" (used by libc 6)
 789 that corresponds directly to
 790 .IR sys_select ()
 791 and similarly
 792 .IR __NR_mmap2 .
 793 .\" .PP
 794 .\" Two system call numbers,
 795 .\" .IR __NR__llseek
 796 .\" and
 797 .\" .IR __NR__sysctl
 798 .\" have an additional underscore absent in
 799 .\" .IR sys_llseek ()
 800 .\" and
 801 .\" .IR sys_sysctl ().
 802 .\"
 803 .\" In kernel 2.1.81,
 804 .\" .BR lchown (2)
 805 .\" and
 806 .\" .BR chown (2)
 807 .\" were swapped; that is,
 808 .\" .BR lchown (2)
 809 .\" was added with the semantics that were then current for
 810 .\" .BR chown (2),
 811 .\" and the semantics of the latter call were changed to what
 812 .\" they are today.
 813 .SH SEE ALSO
 814 .BR syscall (2),
 815 .BR unimplemented (2),
 816 .BR libc (7)