Name
mkfifo - make a FIFO special file (a named pipe)
Synopsis
#include <>#include <>
int mkfifo(const char *pathname, mode_t mode);
Description
mkfifo() makes a FIFO special file with name pathname. mode specifies the
FIFO's permissions. It is modified by the process's umask in the usual way: the permissions of the created file are (mode &
~umask).
A FIFO special file is similar to a pipe, except that it is created
in a different way. Instead of being an anonymous communications
channel, a FIFO special
file is entered into the file system by calling mkfifo().
Once you have created a FIFO special file in this way, any
process can open it for reading or writing, in the same way as an
ordinary file. However, it has
to be open at both ends simultaneously before you can proceed to do any
input or output operations on it. Opening a FIFO for reading normally
blocks until some
other process opens the same FIFO for writing, and vice versa. See (7) for non-blocking handling of FIFO special files.
Return Value
On success
mkfifo() returns 0. In the case of an error, -1 is returned (in which case,
errno is set appropriately).
Errors
- EACCES
- One of the directories in pathname did not allow search (execute) permission.
- EEXIST
- pathname already exists.
- ENAMETOOLONG
- Either the total length of pathname is greater than PATH_MAX, or an individual filename component has a length greater than NAME_MAX.
In the GNU system, there is no imposed limit on overall filename length,
but some file systems may place limits on the length of a component.
- ENOENT
- A directory component in pathname does not exist or is a dangling symbolic link.
- ENOSPC
- The directory or filesystem has no room for the new file.
- ENOTDIR
- A component used as a directory in pathname is not, in fact, a directory.
- EROFS
- pathname refers to a read-only filesystem.
Conforming to
POSIX.1-2001.
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