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@(#)mkfifo.2 8.1 (Berkeley) 6/4/93
.Dd July 29, 2013 .Dt MKFIFO 2 .Os .Sh NAME .Nm mkfifo , .Nm mkfifoat .Nd make a fifo file .Sh LIBRARY .Lb libc .Sh SYNOPSIS n sys/stat.h .Ft int .Fn mkfifo "const char *path" "mode_t mode" n sys/stat.h n fcntl.h .Ft int .Fn mkfifoat "int fd" "const char *path" "mode_t mode" .Sh DESCRIPTION .Fn mkfifo creates a new fifo file with name .Fa path . The access permissions are specified by .Fa mode and restricted by the .Xr umask 2 of the calling process.
p
.Fn mkfifoat
works the same way as
.Fn mkfifo
except if
.Fa path
is relative.
In that case, it is looked up from a directory whose file
descriptor was passed as
.Fa fd .
Search permission is required on this directory.
(These alternatives await a decision about the semantics of O_SEARCH)
Search permission is required on this directory
except if
.Fa fd
was opened with the
.Dv O_SEARCH
flag.
- or -
This file descriptor must have been opened with the
.Dv O_SEARCH
flag.
.Fa fd
can be set to
.Dv AT_FDCWD
in order to specify the current directory.
p The fifo's owner ID is set to the process's effective user ID. The fifo's group ID is set to that of the parent directory in which it is created. .Sh RETURN VALUES .Rv -std mkfifo mkfifoat .Sh ERRORS .Fn mkfifo and .Fn mkfifoat will fail and no fifo will be created if: l -tag -width Er t Bq Er EACCES Search permission is denied for a component of the path prefix. t Bq Er EDQUOT The directory in which the entry for the new fifo is being placed cannot be extended because the user's quota of disk blocks on the file system containing the directory has been exhausted. Or, the user's quota of inodes on the file system on which the fifo is being created has been exhausted. t Bq Er EEXIST The named file exists. t Bq Er EFAULT .Fa path points outside the process's allocated address space. t Bq Er EIO An .Tn I/O error occurred while making the directory entry or allocating the inode. Or, an .Tn I/O error occurred while reading from or writing to the file system. t Bq Er ELOOP Too many symbolic links were encountered in translating the pathname. t Bq Er ENAMETOOLONG A component of a pathname exceeded rq Dv NAME_MAX characters, or an entire path name exceeded rq Dv PATH_MAX characters. t Bq Er ENOENT A component of the path prefix does not exist. t Bq Er ENOSPC The directory in which the entry for the new fifo is being placed cannot be extended because there is no space left on the file system containing the directory. Or, there are no free inodes on the file system on which the fifo is being created. t Bq Er ENOTDIR A component of the path prefix is not a directory. t Bq Er EOPNOTSUPP The kernel has not been configured to support fifo's. t Bq Er EROFS The named file resides on a read-only file system. .El
p In addition, .Fn mkfifoat will fail if: l -tag -width Er t Bq Er EBADF .Fa path does not specify an absolute path and .Fa fd is neither .Dv AT_FDCWD nor a valid file descriptor open for reading or searching. t Bq Er ENOTDIR .Fa path is not an absolute path and .Fa fd is a file descriptor associated with a non-directory file. .El .Sh SEE ALSO .Xr chmod 2 , .Xr stat 2 , .Xr umask 2 .Sh STANDARDS The .Nm mkfifo function call conforms to .St -p1003.1-90 . .Fn mkfifoat conforms to .St -p1003.1-2008 .
Indexes created Sun Sep 21 20:09:37 GMT 2025