1.\" Copyright (c) 1990, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.Dd March 30, 2020 29.Dt MKFIFO 2 30.Os 31.Sh NAME 32.Nm mkfifo , 33.Nm mkfifoat 34.Nd make a fifo file 35.Sh LIBRARY 36.Lb libc 37.Sh SYNOPSIS 38.In sys/types.h 39.In sys/stat.h 40.Ft int 41.Fn mkfifo "const char *path" "mode_t mode" 42.Ft int 43.Fn mkfifoat "int fd" "const char *path" "mode_t mode" 44.Sh DESCRIPTION 45The 46.Fn mkfifo 47system call 48creates a new fifo file with name 49.Fa path . 50The access permissions are 51specified by 52.Fa mode 53and restricted by the 54.Xr umask 2 55of the calling process. 56.Pp 57The fifo's owner ID is set to the process's effective user ID. 58The fifo's group ID is set to that of the parent directory in 59which it is created. 60.Pp 61The 62.Fn mkfifoat 63system call is equivalent to 64.Fn mkfifo 65except in the case where 66.Fa path 67specifies a relative path. 68In this case the newly created FIFO is created relative to the 69directory associated with the file descriptor 70.Fa fd 71instead of the current working directory. 72If 73.Fn mkfifoat 74is passed the special value 75.Dv AT_FDCWD 76in the 77.Fa fd 78parameter, the current working directory is used and the behavior is 79identical to a call to 80.Fn mkfifo . 81.Sh RETURN VALUES 82.Rv -std mkfifo 83.Sh ERRORS 84The 85.Fn mkfifo 86system call 87will fail and no fifo will be created if: 88.Bl -tag -width Er 89.It Bq Er ENOTSUP 90The kernel has not been configured to support fifo's. 91.It Bq Er ENOTDIR 92A component of the path prefix is not a directory. 93.It Bq Er ENAMETOOLONG 94A component of a pathname exceeded 255 characters, 95or an entire path name exceeded 1023 characters. 96.It Bq Er ENOENT 97A component of the path prefix does not exist. 98.It Bq Er EACCES 99A component of the path prefix denies search permission, or write permission 100is denied on the parent directory of the fifo to be created. 101.It Bq Er ELOOP 102Too many symbolic links were encountered in translating the pathname. 103.It Bq Er EROFS 104The named file would reside on a read-only file system. 105.It Bq Er EEXIST 106The named file exists. 107.It Bq Er EPERM 108The parent directory of the named file has its immutable flag set, see the 109.Xr chflags 2 110manual page for more information. 111.It Bq Er ENOSPC 112The directory in which the entry for the new fifo is being placed 113cannot be extended because there is no space left on the file 114system containing the directory. 115.It Bq Er ENOSPC 116There are no free inodes on the file system on which the 117fifo is being created. 118.It Bq Er EDQUOT 119The directory in which the entry for the new fifo 120is being placed cannot be extended because the 121user's quota of disk blocks on the file system 122containing the directory has been exhausted. 123.It Bq Er EDQUOT 124The user's quota of inodes on the file system on 125which the fifo is being created has been exhausted. 126.It Bq Er EIO 127An 128.Tn I/O 129error occurred while making the directory entry or allocating the inode. 130.It Bq Er EINTEGRITY 131Corrupted data was detected while reading from the file system. 132.It Bq Er EFAULT 133The 134.Fa path 135argument 136points outside the process's allocated address space. 137.El 138.Pp 139In addition to the errors returned by the 140.Fn mkfifo , 141the 142.Fn mkfifoat 143may fail if: 144.Bl -tag -width Er 145.It Bq Er EBADF 146The 147.Fa path 148argument does not specify an absolute path and the 149.Fa fd 150argument is neither 151.Dv AT_FDCWD 152nor a valid file descriptor open for searching. 153.It Bq Er ENOTDIR 154The 155.Fa path 156argument is not an absolute path and 157.Fa fd 158is neither 159.Dv AT_FDCWD 160nor a file descriptor associated with a directory. 161.El 162.Sh SEE ALSO 163.Xr chflags 2 , 164.Xr chmod 2 , 165.Xr mknod 2 , 166.Xr stat 2 , 167.Xr umask 2 168.Sh STANDARDS 169The 170.Fn mkfifo 171system call is expected to conform to 172.St -p1003.1-90 . 173The 174.Fn mkfifoat 175system call follows The Open Group Extended API Set 2 specification. 176.Sh HISTORY 177The 178.Fn mkfifoat 179system call appeared in 180.Fx 8.0 . 181