NAME
mkfifo,
mkfifoat —
make a fifo file
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <sys/stat.h>
int
mkfifo(
const char
*path,
mode_t mode);
#include <sys/stat.h>
#include <fcntl.h>
int
mkfifoat(
int
fd,
const char *path,
mode_t mode);
DESCRIPTION
mkfifo() 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.
mkfifoat() works the same way as
mkfifo()
except if
path is relative. In that case, it is looked
up from a directory whose file descriptor was passed as
fd. Search permission is required on this directory.
fd can be set to
AT_FDCWD
in
order to specify the current directory.
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.
RETURN VALUES
The
mkfifo() and
mkfifoat() functions return
the value 0 if successful; otherwise the value -1 is returned and
the global variable
errno is set to indicate the error.
ERRORS
mkfifo() and
mkfifoat() will fail and no
fifo will be created if:
-
-
- [
EACCES
]
- Search permission is denied for a component of the path
prefix.
-
-
- [
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.
-
-
- [
EEXIST
]
- The named file exists.
-
-
- [
EFAULT
]
- path points outside the process's
allocated address space.
-
-
- [
EIO
]
- An I/O error occurred while making the directory entry or
allocating the inode. Or, an I/O error occurred while reading from or
writing to the file system.
-
-
- [
ELOOP
]
- Too many symbolic links were encountered in translating the
pathname.
-
-
- [
ENAMETOOLONG
]
- A component of a pathname exceeded
{
NAME_MAX
} characters, or an entire path name
exceeded {PATH_MAX
} characters.
-
-
- [
ENOENT
]
- A component of the path prefix does not exist.
-
-
- [
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.
-
-
- [
ENOTDIR
]
- A component of the path prefix is not a directory.
-
-
- [
EOPNOTSUPP
]
- The kernel has not been configured to support fifo's.
-
-
- [
EROFS
]
- The named file resides on a read-only file system.
In addition,
mkfifoat() will fail if:
-
-
- [
EBADF
]
- path does not specify an absolute
path and fd is neither
AT_FDCWD
nor a valid file descriptor open for
reading or searching.
-
-
- [
ENOTDIR
]
- path is not an absolute path and
fd is a file descriptor associated with a
non-directory file.
SEE ALSO
chmod(2),
stat(2),
umask(2)
STANDARDS
The
mkfifo function call conforms to
IEEE Std
1003.1-1990 (“POSIX.1”).
mkfifoat()
conforms to
IEEE Std 1003.1-2008
(“POSIX.1”).