mkfifo
, mkfifoat
—
make a fifo file
Standard C Library (libc, -lc)
#include <sys/types.h>
#include <sys/stat.h>
int
mkfifo
(const
char *path, mode_t
mode);
int
mkfifoat
(int
fd, const char
*path, mode_t
mode);
The mkfifo
() system call creates a new fifo file with
name path. The access permissions are specified by
mode and restricted by the
umask(2)
of the calling process.
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.
The mkfifoat
() system call is equivalent
to mkfifo
() except in the case where
path specifies a relative path. In this case the newly
created FIFO is created relative to the directory associated with the file
descriptor fd instead of the current working
directory. If mkfifoat
() is passed the special value
AT_FDCWD
in the fd parameter,
the current working directory is used and the behavior is identical to a
call to mkfifo
().
The mkfifo
() function returns the value 0 if
successful; otherwise the value -1 is returned and the global variable
errno is set to indicate the error.
The mkfifo
() system call will fail and no fifo will be
created if:
- [
ENOTSUP
]
- The kernel has not been configured to support fifo's.
- [
ENOTDIR
]
- A component of the path prefix is not a directory.
- [
ENAMETOOLONG
]
- A component of a pathname exceeded 255 characters, or an entire path name
exceeded 1023 characters.
- [
ENOENT
]
- A component of the path prefix does not exist.
- [
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.
- [
ELOOP
]
- Too many symbolic links were encountered in translating the pathname.
- [
EROFS
]
- The named file would reside on a read-only file system.
- [
EEXIST
]
- The named file exists.
- [
EPERM
]
- The parent directory of the named file has its immutable flag set, see the
chflags(2)
manual page for more information.
- [
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.
- [
ENOSPC
]
- There are no free inodes on the file system on which the fifo is being
created.
- [
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.
- [
EDQUOT
]
- The user's quota of inodes on the file system on which the fifo is being
created has been exhausted.
- [
EIO
]
- An I/O error occurred while making the directory entry or allocating the
inode.
- [
EINTEGRITY
]
- Corrupted data was detected while reading from the file system.
- [
EFAULT
]
- The path argument points outside the process's
allocated address space.
In addition to the errors returned by the
mkfifo
(), the mkfifoat
() may
fail if:
- [
EBADF
]
- The path argument does not specify an absolute path
and the fd argument is neither
AT_FDCWD
nor a valid file descriptor open for
searching.
- [
ENOTDIR
]
- The path argument is not an absolute path and
fd is neither
AT_FDCWD
nor a
file descriptor associated with a directory.
The mkfifo
() system call is expected to conform to
IEEE Std 1003.1-1990 (“POSIX.1”). The
mkfifoat
() system call follows The Open Group Extended
API Set 2 specification.
The mkfifoat
() system call appeared in
FreeBSD 8.0.