1.\" $OpenBSD: options.4,v 1.236 2014/04/18 11:19:45 henning Exp $ 2.\" $NetBSD: options.4,v 1.21 1997/06/25 03:13:00 thorpej Exp $ 3.\" 4.\" Copyright (c) 1998 Theo de Raadt 5.\" Copyright (c) 1998 Todd Miller 6.\" Copyright (c) 1998 Gene Skonicki 7.\" Copyright (c) 1996 8.\" Perry E. Metzger. All rights reserved. 9.\" 10.\" Redistribution and use in source and binary forms, with or without 11.\" modification, are permitted provided that the following conditions 12.\" are met: 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in the 17.\" documentation and/or other materials provided with the distribution. 18.\" 3. All advertising materials mentioning features or use of this software 19.\" must display the following acknowledgment: 20.\" This product includes software developed for the NetBSD Project 21.\" by Perry E. Metzger. 22.\" 4. The name of the author may not be used to endorse or promote products 23.\" derived from this software without specific prior written permission. 24.\" 25.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 26.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 27.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 28.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 29.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 30.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 31.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 32.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 33.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 34.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 35.\" 36.\" 37.Dd $Mdocdate: April 18 2014 $ 38.Dt OPTIONS 4 39.Os 40.Sh NAME 41.Nm options 42.Nd kernel configuration options 43.Sh SYNOPSIS 44.Cd option ... 45.Sh DESCRIPTION 46This manual page describes a number of miscellaneous kernel 47configuration options that may be specified in a kernel config file. 48See 49.Xr config 8 50for information on how to configure and build kernels. 51.Em Note: 52options are passed to the compile process as 53.Fl D 54flags to the C compiler. 55.Sh COMPATIBILITY OPTIONS 56.Bl -ohang 57.It Cd option COMPAT_43 58This option enables compatibility with 59.Bx 4.3 . 60It provides backwards compatibility with the 61.Dq old 62SIOC[GS]IF{ADDR,DSTADDR,BRDADDR,NETMASK} interface ioctls, including 63binary compatibility for code written before the introduction of the 64.Li sa_len 65field in sockaddrs. 66.It Cd option COMPAT_LINUX 67On those architectures that support it, this enables binary 68compatibility with 69.Em Linux 70ELF applications built for the same architecture. 71This option is supported on the i386 architecture. 72See 73.Xr compat_linux 8 . 74.El 75.Sh DEBUGGING OPTIONS 76.Bl -ohang 77.It Cd makeoptions DEBUG="-g" 78The 79.Fl g 80flag causes 81.Pa bsd.gdb 82to be built in addition to 83.Pa bsd . 84.Pa bsd.gdb 85is useful for debugging kernels and their crash dumps with gdb. 86A crash dump can be debugged by starting 87.Xr gdb 1 88with the kernel name 89.Pf ( Pa bsd.gdb ) 90as an argument (no core file) and then use the 91.Xr gdb 1 92command 93.Dq target kvm COREFILE . 94.It Cd makeoptions PROF="-pg" 95The 96.Fl pg 97flag causes the kernel to be compiled with support for profiling. 98The 99.Cm option GPROF 100is required for the kernel compile to succeed. 101.It Cd option ACCOUNTING 102Adds support for the 103.Xr acct 2 104system call. 105.It Cd option DDB 106Compiles in a kernel debugger for diagnosing kernel problems. 107See 108.Xr ddb 4 109for details. 110.It Cd option DDB_SAFE_CONSOLE 111Allows a break into the kernel debugger during boot. 112Useful when debugging problems that can cause 113.Xr init 8 114to fail. 115.It Cd option DDB_STRUCT 116Compiles in symbolic information about the various data structures used by the 117kernel, for use within the kernel debugger. 118This option is currently not supported on alpha, m88k and vax based 119platforms. 120.It Cd option DEBUG 121Turns on miscellaneous kernel debugging. 122Since options are turned into preprocessor defines (see above), 123.Cm option DEBUG 124is equivalent to doing a 125.Em #define DEBUG 126throughout the kernel. 127Much of the kernel has 128.Em #ifdef DEBUG 129conditional debugging code. 130Note that many parts of the kernel (typically device drivers) include their own 131.Em #ifdef XXX_DEBUG 132conditionals instead. 133This option also turns on certain other options, notably 134.Cm option KMEMSTATS . 135.It Cd option DIAGNOSTIC 136Adds code to the kernel that does internal consistency checks. 137This code will cause the kernel to panic if corruption of internal data 138structures is detected. 139.It Cd option GPROF 140Adds code to the kernel for kernel profiling with 141.Xr kgmon 8 . 142.It Cd option KGDB 143Compiles in a remote kernel debugger stub for diagnosing kernel problems 144using the 145.Dq remote target 146feature of gdb. 147See 148.Xr kgdb 7 149for details. 150.Em Note: 151not available on all architectures. 152.It Cd option KTRACE 153Adds hooks for the system call tracing facility, which allows users to 154watch the system call invocation behavior of processes. 155See 156.Xr ktrace 1 157for details. 158.It Cd option NO_PROPOLICE 159Do not compile the kernel with the ProPolice stack protection. 160See 161.Xr gcc-local 1 162for more information about ProPolice. 163.It Cd option PTRACE 164Adds hooks for the process tracing facility, allowing a process to 165control and observe another process. 166See 167.Xr ptrace 2 168for details. 169.It Cd option SMALL_KERNEL 170Removes some features and some optimizations from the kernel to reduce the 171size of the resulting kernel binary. 172This option is used on some installation media and should not be used 173for general purpose kernels. 174.It Cd option VFSLCKDEBUG 175Turns on debugging for the Virtual File System interface. 176See 177.Xr vfs 9 178for details. 179.El 180.Sh FILE SYSTEMS 181.Bl -ohang 182.It Cd option CD9660 183Includes code for the ISO 9660 + Rock Ridge file system, which is the 184standard file system used on many CD-ROMs. 185It also supports Joliet extensions. 186See 187.Xr mount_cd9660 8 188for details. 189.It Cd option EXT2FS 190Includes code implementing the Second Extended File System 191.Em ( EXT2FS ) , 192commonly used on the Linux operating system. 193This option is provided here for compatibility. 194Some specific features of 195.Em EXT2FS 196like the "behavior on errors" are not implemented. 197This file system 198can't be used with 199.Li uid_t 200or 201.Li gid_t 202values greater than 65535. 203Also, the filesystem will not function correctly on architectures with 204differing byte-orders. 205That is, a big-endian machine will not be able to read an 206ext2fs filesystem created on an i386 or other little-endian machine. 207See 208.Xr mount_ext2fs 8 209for details. 210.It Cd option FFS 211Includes code implementing the Berkeley Fast File System 212.Em ( FFS ) . 213Most machines need this if they are not running diskless. 214.It Cd option FFS2 215Includes code implementing the enhanced Fast File System 216.Em ( FFS2 ) . 217.It Cd option MFS 218Include the memory file system 219.Em ( MFS ) . 220This file system stores files in swappable memory, and produces 221notable performance improvements when it is used as the file store 222for 223.Pa /tmp 224or similar mount points. 225See 226.Xr mount_mfs 8 227for details. 228.It Cd option MSDOSFS 229Includes support for the MS-DOS FAT file system. 230The kernel also implements the Windows 95 231extensions which permit the use of longer, mixed-case file names. 232See 233.Xr mount_msdos 8 234and 235.Xr fsck_msdos 8 236for details. 237.It Cd option NFSCLIENT 238Include the client side of the 239.Em NFS 240(Network File System) remote file sharing protocol. 241Although the bulk of the code implementing 242.Em NFS 243is kernel based, several user level daemons are needed for it to work. 244See 245.Xr mount_nfs 8 246for details on NFS. 247.It Cd option NTFS 248Includes support for reading NTFS file systems. 249See 250.Xr mount_ntfs 8 251for details. 252.It Cd option PROCFS 253Includes code for a special file system (conventionally mounted on 254.Pa /proc ) 255in which the process space becomes visible in the file system. 256Among other things, the memory spaces of processes running on the system are 257visible as files, and signals may be sent to processes by writing to 258.Pa ctl 259files in the procfs namespace. 260See 261.Xr mount_procfs 8 262for details. 263.It Cd option UDF 264Includes code for the UDF file systems typically found on DVD discs. 265See 266.Xr mount_udf 8 267for details. 268.It Cd option TMPFS 269Includes code for the TMPFS efficient memory file system. 270See 271.Xr mount_tmpfs 8 272for details. 273.El 274.Sh FILE SYSTEM OPTIONS 275.Bl -ohang 276.It Cd option BUFCACHEPERCENT= Ns Ar integer 277Percentage of RAM to use as a file system buffer. 278It defaults to 20. 279.It Cd option EXT2FS_SYSTEM_FLAGS 280This option changes the behavior of the APPEND and IMMUTABLE flags 281for a file on an 282.Em EXT2FS 283filesystem. 284Without this option, the superuser or owner of the file can set and clear them. 285With this option, only the superuser can set them, and they can't be cleared 286if the securelevel is greater than 0. 287See also 288.Xr chflags 1 . 289.It Cd option FFS_SOFTUPDATES 290Enables a scheme that uses partial ordering of buffer cache operations 291to allow metadata updates in FFS to happen asynchronously, increasing write 292performance significantly. 293Normally, the FFS filesystem writes metadata updates synchronously which exacts 294a performance penalty in favor of filesystem integrity. 295With soft updates, the performance of asynchronous writes is gained while 296retaining the safety of synchronous metadata updates. 297.Pp 298Soft updates must be enabled on a per-filesystem basis. 299See 300.Xr mount 8 301for details. 302.Pp 303Processors with a small kernel address space, such as the sun4 and sun4c, do 304not have enough kernel memory to support soft updates. 305Attempts to use this option with these CPUs will cause a kernel hang or panic 306after a short period of use as the kernel will quickly run out of memory. 307This is not related to the amount of physical memory present in the machine -- 308it is a limitation of the CPU architecture itself. 309.It Cd option FIFO 310Adds support for 311.At V 312style FIFOs (i.e., 313.Dq named pipes ) . 314This option is recommended in almost all cases as many programs use these. 315.It Cd option NFSSERVER 316Include the server side of the 317.Em NFS 318(Network File System) remote file sharing protocol. 319Although the bulk of the code implementing 320.Em NFS 321is kernel based, several user level daemons are needed for it to 322work. 323See 324.Xr mountd 8 325and 326.Xr nfsd 8 327for details. 328.It Cd option QUOTA 329Enables kernel support for file system quotas. 330See 331.Xr quotaon 8 , 332.Xr edquota 8 , 333.Xr repquota 8 , 334and 335.Xr quota 1 336for details. 337Note that quotas only work on 338.Dq ffs 339file systems, although 340.Xr rpc.rquotad 8 341permits them to be accessed over 342.Em NFS . 343.It Cd option UFS_DIRHASH 344This option enables using an in memory hash table to speed lookups 345in large directories. 346.El 347.Sh MISCELLANEOUS OPTIONS 348.Bl -ohang 349.It Cd option APERTURE 350Provide in-kernel support for controlling VGA framebuffer mapping 351and PCI configuration registers by user-processes 352(such as an X Window System server). 353This option is supported on the 354.Va alpha , 355.Va amd64 , 356.Va i386 , 357.Va macppc , 358and 359.Va sparc64 360architectures. 361.It Cd option BOOT_CONFIG 362Adds support for the 363.Fl c 364boot option (User Kernel Config). 365Allows modification of kernel settings (e.g., device parameters) before 366booting the system. 367.It Cd option CRYPTO 368Enables support for the kernel cryptographic framework. 369See 370.Xr crypto 9 371for details. 372While not IP specific, this option is usually used in conjunction with option 373.Em IPSEC . 374.It Cd option EISAVERBOSE 375Makes the boot process more verbose for EISA peripherals. 376.It Cd option INSECURE 377Hardwires the kernel security level at \-1. 378This means that the system always runs in securelevel 0 mode, even when 379running multiuser. 380See 381.Xr init 8 382for details on the implications of this. 383The kernel secure level may be manipulated by the superuser by altering the 384.Em kern.securelevel 385sysctl variable. 386(It should be noted that the securelevel may only be lowered by a call from 387process ID 1, i.e., 388.Xr init 8 . ) 389See also 390.Xr sysctl 8 391and 392.Xr sysctl 3 . 393.It Cd option KMEMSTATS 394The kernel memory allocator, 395.Xr malloc 9 , 396will keep statistics on its performance if this option is enabled. 397Note that this option is silently turned on by the 398.Cm DEBUG 399option. 400.It Cd option LKM 401Enables support for loadable kernel modules. 402See 403.Xr lkm 4 404for details. 405.Em Note: 406This option is not yet available on all architectures. 407.It Cd option MACOBIOVERBOSE 408Makes the boot process more verbose for OBIO peripherals on the 409.Va macppc 410architecture. 411.It Cd option MULTIPROCESSOR 412On those architectures that have it, this enables multiprocessor support. 413.It Cd option PCIVERBOSE 414Makes the boot process more verbose for PCI peripherals 415(vendor names and other information is printed, etc.). 416.It Cd option PCMCIAVERBOSE 417Makes the boot process more verbose for PCMCIA peripherals. 418.It Cd option USER_LDT 419Enable userland manipulation of per-process 420Local Descriptor Table (LDT) entries; 421see 422.Xr i386_set_ldt 2 423and the 424.Va machdep.userldt 425.Xr sysctl 8 . 426This option is supported on the 427.Va i386 428architecture. 429.It Cd option USER_PCICONF 430Enables the user level access to the PCI bus configuration space 431through ioctls on the 432.Pa /dev/pci 433device. 434It's used by the 435.Xr Xorg 1 436server on some architectures. 437See 438.Xr pci 4 439for details. 440.It Cd option UVM_SWAP_ENCRYPT 441Enables kernel support for encrypting pages that are written out to 442swap storage. 443Swap encryption prevents sensitive data from remaining 444on the disk even after the operating system has been shut down. 445This option should be turned on if cryptographic filesystems are used. 446The sysctl variable 447.Em vm.swapencrypt.enable 448controls its behaviour. 449See 450.Xr sysctl 8 451and 452.Xr sysctl 3 453for details. 454.El 455.Sh NETWORKING OPTIONS 456.Bl -ohang 457.It Cd option ENCDEBUG 458This option enables debugging information to be conditionally logged 459in case IPSEC encounters errors. 460The option 461.Em IPSEC 462is required along with this option. 463Debug logging can be turned on/off through the use of the 464.Em net.inet.ip.encdebug 465sysctl variable. 466If 467.Em net.inet.ip.encdebug 468is 1, debug logging is on. 469See 470.Xr sysctl 8 471and 472.Xr sysctl 3 473for details. 474.It Cd option INET 475Includes support for the TCP/IP protocol stack. 476This option is currently required. 477See 478.Xr inet 4 479for details. 480.It Cd option INET6 481Includes support for the IPv6 protocol stack. 482See 483.Xr inet6 4 484for details. 485Unlike 486.Em INET , 487.Em INET6 488enables multicast routing code as well. 489This option requires 490.Em INET 491at this moment, but it should not. 492.It Cd option IPSEC 493This option enables IP security protocol support. 494See 495.Xr ipsec 4 496for more details. 497.It Cd option KEY 498Enables PFKEYv2 (RFC 2367) support. 499While not IP specific, this option is usually used in conjunction with option 500.Em IPSEC . 501.It Cd option MROUTING 502Includes support for IP multicast routers. 503.Em INET 504should be set along with this. 505Multicast routing is controlled by the 506.Xr mrouted 8 507daemon. 508.It Cd option ND6_DEBUG 509The option sets the default value of 510.Em net.inet6.icmp6.nd6_debug 511to 1, 512for debugging IPv6 neighbor discovery protocol handling. 513See 514.Xr sysctl 3 515for details. 516.It Cd option PIPEX 517Includes pipex in-kernel acceleration for PPPoE, L2TP or PPTP. 518See 519.Xr pipex 4 520for details. 521.It Cd option PPP_BSDCOMP 522Enables BSD compressor for PPP connections. 523.It Cd option PPP_DEFLATE 524For use in conjunction with PPP_BSDCOMP; provides an interface to zlib for PPP 525for deflate compression/decompression. 526.It Cd option SOCKET_SPLICE 527Enables zero-copy socket splicing in the kernel. 528See 529.Dv SO_SPLICE 530in 531.Xr setsockopt 2 532and 533.Xr sosplice 9 534for details. 535.It Cd option TCP_ECN 536Turns on Explicit Congestion Notification (RFC 3168). 537.Em ECN 538allows intermediate routers to use the Congestion Experienced 539codepoint in the IP header as an indication of congestion, and allows 540TCP to adjust the transmission rate using this signal. 541Both communication endpoints negotiate enabling 542.Em ECN 543functionality at the TCP connection establishment. 544.It Cd option TCP_FACK 545Turns on forward acknowledgements allowing a more precise estimate of 546outstanding data during the fast recovery phase by using 547.Em SACK 548information. 549This option can only be used together with 550.Em TCP_SACK . 551.It Cd option TCP_SACK 552Turns on selective acknowledgements. 553Additional information about 554segments already received can be transmitted back to the sender, 555thus indicating segments that have been lost and allowing for 556a swifter recovery. 557Both communication endpoints need to support 558.Em SACK . 559The fallback behaviour is NewReno fast recovery phase, which allows 560one lost segment to be recovered per round trip time. 561When more than one segment has been dropped per window, the transmission can 562continue without waiting for a retransmission timeout. 563.It Cd option TCP_SIGNATURE 564Turns on support for the TCP MD5 Signature option (RFC 2385). 565This is used by 566Internet backbone routers to provide per-packet authentication for the TCP 567packets used to communicate BGP routing information. 568You will also need a 569routing daemon that supports this option in order to actually use it. 570.El 571.Sh OPERATION RELATED OPTIONS 572.Bl -ohang -compact 573.It Cd option BUFPAGES= Ns Ar value 574.It Cd option NBUF= Ns Ar value 575These options set the number of pages available for the buffer cache. 576Their default value is a machine dependent value, often calculated as 577between 5% and 10% of total available RAM. 578.Pp 579.It Cd option DST= Ns Ar value 580If 581.Ar value 582is non-zero, indicates that the hardware realtime clock device 583is one hour ahead of the offset given in 584.Sq TIMEZONE , 585due to Daylight Saving Time (DST). 586If 587.Ar value 588is zero, the hardware realtime clock device is not in Daylight Saving Time. 589.Pp 590.It Cd option NKMEMPAGES= Ns Ar value 591.It Cd option NKMEMPAGES_MAX= Ns Ar value 592Size of kernel malloc area in PAGE_SIZE-sized logical pages. 593This area is covered by the kernel submap 594.Em kmem_map . 595The kernel attempts to auto-size this map based on the amount of 596physical memory in the system. 597Platform-specific code may place bounds on this computed size, 598which may be viewed with the 599.Xr sysctl 8 600variable 601.Em vm.nkmempages . 602See 603.Pa /usr/include/machine/param.h 604for the default upper bound. 605The related option 606.Sq NKMEMPAGES_MAX 607allows the bounds to be overridden in the kernel configuration file 608in the event the computed value is insufficient resulting in an 609.Dq out of space in kmem_map 610panic. 611.Pp 612.It Cd option \&"TIMEZONE= Ns Ar value Ns Cm \&" 613.Ar value 614indicates the time zone offset of the hardware realtime clock device, 615in minutes, 616from UTC. 617It is useful when the hardware realtime clock device is configured 618with local time, 619when dual-booting 620.Ox 621with other operating systems on a single machine. 622For instance, if the hardware realtime clock is set to Tokyo time, 623.Ar value 624should be 625.Li \&-540 626as Tokyo local time is 9 hours ahead of UTC. 627Double quotes are needed when specifying a negative 628.Ar value . 629.El 630.Sh SCSI SUBSYSTEM OPTIONS 631.Bl -ohang 632.It Cd option SCSI_DELAY= Ns Ar value 633Delay for 634.Ar value 635seconds before starting to probe the first SCSI bus. 636This can be used if a SCSI device needs extra time to get ready. 637.It Cd option SCSIDEBUG 638Enable printing of SCSI subsystem debugging info to the console. 639Each of 640.Em SCSIDEBUG_LEVEL , 641.Em SCSIDEBUG_BUSES , 642.Em SCSIDEBUG_TARGETS 643and 644.Em SCSIDEBUG_LUNS 645must have non-zero values for any debugging info to be printed. 646Only 647.Em SCSIDEBUG_LEVEL 648has a default value (SDEV_DB1 | SDEV_DB2) that is non-zero. 649.It Cd option SCSIDEBUG_BUSES= Ns Ar value 650Define which SCSI buses will print debug info. 651Each bit enables debugging info for the corresponding bus. 652e.g. a value of 0x1 enables debug info for bus 0. 653.It Cd option SCSIDEBUG_LEVEL= Ns Ar value 654Define which of the four levels of debugging info are printed. 655Each bit enables a level, and multiple levels are specified by setting multiple 656bits. 657.Bd -literal -offset indent 6580x0010 (SDEV_DB1) SCSI commands, errors, and data 6590x0020 (SDEV_DB2) routine flow 6600x0040 (SDEV_DB3) routine internals 6610x0080 (SDEV_DB4) miscellaneous addition debugging 662.Ed 663.Pp 664If 665.Em SCSIDEBUG_LEVEL 666is undefined, a value of 0x0030 (SDEV_DB1|SDEV_DB2) is used. 667.It Cd option SCSIDEBUG_LUNS= Ns Ar value 668Define which SCSI luns will print debug info. 669Each bit enables debugging info for the corresponding lun. 670.It Cd option SCSIDEBUG_TARGETS= Ns Ar value 671Define which SCSI targets will print debug info. 672Each bit enables debugging info for the corresponding target. 673.It Cd option SCSITERSE 674Terser SCSI error messages. 675This omits the table for decoding ASC/ASCQ info, saving about 30KB. 676.El 677.Sh SYSTEM V IPC OPTIONS 678.Bl -ohang 679.It Cd option SEMMNI= Ns Ar value 680Number of semaphore identifiers (also called semaphore handles 681and semaphore sets) available in the system. 682Default value is 10. 683The kernel allocates memory for the control structures at startup, 684so arbitrarily large values should be avoided. 685.It Cd option SEMMNS= Ns Ar value 686Maximum number of semaphores in all sets in the system. 687Default value is 60. 688.It Cd option SEMMNU= Ns Ar value 689Maximum number of semaphore undo structures in the system. 690Default value is 30. 691.It Cd option SEMUME= Ns Ar value 692Maximum number of per-process undo operation entries in the 693system. 694Semaphore undo operations are invoked by the kernel when 695.Xr semop 2 696is called with the SEM_UNDO flag and the process holding 697the semaphores terminates unexpectedly. 698Default value is 10. 699.It Cd option SHMMAXPGS= Ns Ar value 700Sets the maximum number of 701.At V 702style shared memory pages that are available through the 703.Xr shmget 2 704system call. 705Default value is 1024 on most architectures. 706See 707.Pa /usr/include/machine/vmparam.h 708for the default. 709.It Cd option SYSVMSG 710Includes support for 711.At V 712style message queues. 713See 714.Xr msgctl 2 , 715.Xr msgget 2 , 716.Xr msgrcv 2 , 717.Xr msgsnd 2 . 718.It Cd option SYSVSEM 719Includes support for 720.At V 721style semaphores. 722See 723.Xr semctl 2 , 724.Xr semget 2 , 725.Xr semop 2 . 726.It Cd option SYSVSHM 727Includes support for 728.At V 729style shared memory. 730See 731.Xr shmat 2 , 732.Xr shmctl 2 , 733.Xr shmdt 2 , 734.Xr shmget 2 . 735.El 736.Sh SEE ALSO 737.Xr intro 4 , 738.Xr files.conf 5 , 739.Xr config 8 , 740.Xr sysctl 8 741.Sh HISTORY 742The 743.Nm 744man page first appeared in 745.Ox 2.3 . 746.Sh BUGS 747The 748.Em INET 749option should not be required. 750