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@(#)mkfifo.2 8.1 (Berkeley) 6/4/93
$FreeBSD: stable/10/lib/libc/sys/mkfifo.2 178245 2008-04-16 13:03:12Z kib $
.Dd April 10, 2008 .Dt MKFIFO 2 .Os .Sh NAME .Nm mkfifo , .Nm mkfifoat .Nd make a fifo file .Sh LIBRARY .Lb libc .Sh SYNOPSIS n sys/types.h n sys/stat.h .Ft int .Fn mkfifo "const char *path" "mode_t mode" .Ft int .Fn mkfifoat "int fd" "const char *path" "mode_t mode" .Sh DESCRIPTION The .Fn mkfifo system call 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 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.
p The .Fn mkfifoat system call is equivalent to .Fn mkfifo except in the case where .Fa path specifies a relative path. In this case the newly created FIFO is created relative to the directory associated with the file descriptor .Fa fd instead of the current working directory. If .Fn mkfifoat is passed the special value .Dv AT_FDCWD in the .Fa fd parameter, the current working directory is used and the behavior is identical to a call to .Fn mkfifo . .Sh RETURN VALUES .Rv -std mkfifo .Sh ERRORS The .Fn mkfifo system call will fail and no fifo will be created if: l -tag -width Er t Bq Er ENOTSUP The kernel has not been configured to support fifo's. t Bq Er ENOTDIR A component of the path prefix is not a directory. t Bq Er ENAMETOOLONG A component of a pathname exceeded 255 characters, or an entire path name exceeded 1023 characters. t Bq Er ENOENT A component of the path prefix does not exist. t Bq Er EACCES A component of the path prefix denies search permission, or write permission is denied on the parent directory of the fifo to be created. t Bq Er ELOOP Too many symbolic links were encountered in translating the pathname. t Bq Er EROFS The named file would reside on a read-only file system. t Bq Er EEXIST The named file exists. t Bq Er EPERM The parent directory of the named file has its immutable flag set, see the .Xr chflags 2 manual page for more information. 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. t Bq Er ENOSPC There are no free inodes on the file system on which the fifo is being created. 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. t Bq Er EDQUOT The user's quota of inodes on the file system on which the fifo is being created has been exhausted. t Bq Er EIO An .Tn I/O error occurred while making the directory entry or allocating the inode. t Bq Er EIO An .Tn I/O error occurred while reading from or writing to the file system. t Bq Er EFAULT The .Fa path argument points outside the process's allocated address space. .El
p In addition to the errors returned by the .Fn mkfifo , the .Fn mkfifoat may fail if: l -tag -width Er t Bq Er EBADF The .Fa path argument does not specify an absolute path and the .Fa fd argument is neither .Dv AT_FDCWD nor a valid file descriptor open for searching. t Bq Er ENOTDIR The .Fa path argument is not an absolute path and .Fa fd is neither .Dv AT_FDCWD nor a file descriptor associated with a directory. .El .Sh SEE ALSO .Xr chflags 2 , .Xr chmod 2 , .Xr mknod 2 , .Xr stat 2 , .Xr umask 2 .Sh STANDARDS The .Fn mkfifo system call is expected to conform to .St -p1003.1-90 . The .Fn mkfifoat system call follows The Open Group Extended API Set 2 specification. .Sh HISTORY The .Fn mkfifoat system call appeared in .Fx 8.0 .