MKFIFO

NAME

mkfifo - make a FIFO special file (a named pipe)

SYNOPSIS

#include <sys/types.h>
#include <sys/stat.h>

int mkfifo(const char *pathname, mode_t mode);

DESCRIPTION

fBmkfifofP makes a FIFO special file with name fIpathnamefP. fImodefP specifies the FIFO's permissions. It is modified by the process's fBumaskfP in the usual way: the permissions of the created file are fB(fPfImodefPfB & ~umask)fP.

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 fBmkfifofP.

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 fifo(4) for non-blocking handling of FIFO special files.

RETURN VALUE

The normal, successful return value from fImkfifofP is fB0fP. In the case of an error, fB-1fP is returned (in which case, fIerrnofP is set appropriately).

ERRORS

EACCES: One of the directories in fIpathnamefP did not allow search (execute) permission.
EEXIST: fIpathnamefP already exists.
ENAMETOOLONG: Either the total length of fIpathnamefP is greater than fBPATH_MAXfP, or an individual file name component has a length greater than fBNAME_MAXfP. In the GNU system, there is no imposed limit on overall file name length, but some file systems may place limits on the length of a component.
ENOENT: A directory component in fIpathnamefP 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 fIpathnamefP is not, in fact, a directory.
EROFS: fIpathnamefP refers to a read-only filesystem.

CONFORMING TO

POSIX.1