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All Rights Reserved. .\" Copyright (c) 2002, Sun Microsystems, Inc. All Rights Reserved. .\" Copyright (c) 2014, Joyent, Inc. .\" .TH MKFIFO 3C "June 18, 2021" .SH NAME mkfifo, mkfifoat \- make a FIFO special file .SH SYNOPSIS .nf #include #include \fBint\fR \fBmkfifo\fR(\fBconst char *\fR\fIpath\fR, \fBmode_t\fR \fImode\fR); .fi .LP .nf \fBint\fR \fBmkfifoat\fR(\fBint\fR \fIfd\fR, \fBconst char *\fR\fIpath\fR, \fBmode_t\fR \fImode\fR); .fi .SH DESCRIPTION The \fBmkfifo()\fR and \fBmkfifoat()\fR functions create a new FIFO special file named by the pathname pointed to by \fIpath\fR. The file permission bits of the new FIFO are initialized from \fImode\fR. The file permission bits of the \fImode\fR argument are modified by the process's file creation mask (see \fBumask\fR(2)). Bits other than the file permission bits in \fImode\fR are ignored. .sp .LP If \fIpath\fR names a symbolic link, \fBmkfifo()\fR and \fBmkfifoat()\fR fail and set \fBerrno\fR to \fBEEXIST\fR. .sp .LP The FIFO's user ID is set to the process's effective user ID. The FIFO's group ID is set to the group ID of the parent directory or to the effective group ID of the process. .sp .LP The \fBmkfifoat()\fR function is equivalent to \fBmkfifo()\fR; however, if \fIpath\fR is a relative path, then it is resolved start at the directory represented by \fIfd\fR. \fIfd\fR may be set to the special value of \fBAT_FDCWD\fR which indicates that the current working directory should be used to start resolving \fIpath\fR. .sp .LP The \fBmkfifo()\fR function calls \fBmknod\fR(2) to create the file. The \fBmkfifoat()\fR function calls \fBmknodat\fR(2) to create the file. .sp .LP Upon successful completion, \fBmkfifo()\fR and \fBmkfifoat()\fR mark for update the \fBst_atime\fR, \fBst_ctime\fR, and \fBst_mtime\fR fields of the file. Also, the \fBst_ctime\fR and \fBst_mtime\fR fields of the directory that contains the new entry are marked for update. .SH RETURN VALUES Upon successful completion, \fB0\fR is returned. Otherwise, \fB\(mi1\fR is returned and \fBerrno\fR is set to indicate the error. .SH ERRORS The \fBmkfifo()\fR and \fBmkfifoat()\fR functions will fail if: .sp .ne 2 .na \fB\fBEACCES\fR\fR .ad .RS 16n A component of the path prefix denies search permission, or write permission is denied on the parent directory of the FIFO to be created. .RE .sp .ne 2 .na \fB\fBEEXIST\fR\fR .ad .RS 16n The named file already exists. .RE .sp .ne 2 .na \fB\fBELOOP\fR\fR .ad .RS 16n A loop exists in symbolic links encountered during resolution of the \fIpath\fR argument. .RE .sp .ne 2 .na \fB\fBENAMETOOLONG\fR\fR .ad .RS 16n The length of the \fIpath\fR argument exceeds {\fBPATH_MAX\fR} or a pathname component is longer than {\fBNAME_MAX\fR}. .RE .sp .ne 2 .na \fB\fBENOENT\fR\fR .ad .RS 16n A component of the path prefix specified by \fIpath\fR does not name an existing directory or \fIpath\fR is an empty string. .RE .sp .ne 2 .na \fB\fBENOSPC\fR\fR .ad .RS 16n The directory that would contain the new file cannot be extended or the file system is out of file-allocation resources. .RE .sp .ne 2 .na \fB\fBENOTDIR\fR\fR .ad .RS 16n A component of the path prefix is not a directory. For \fBmkfifoat()\fR, \fIpath\fR is a relative path and \fIfd\fR is a valid file descriptor which is not a directory. .RE .sp .ne 2 .na \fB\fBEROFS\fR\fR .ad .RS 16n The named file resides on a read-only file system. .RE .sp .LP The \fBmkfifoat()\fR function will fail if: .sp .ne 2 .na .B EBADF .ad .RS 16n The \fIpath\fR argument is a relative path and \fIfd\fR is not a valid file descriptor or the value \fBAT_FDCWD\fR. .RE .sp .LP The \fBmkfifo()\fR function may fail if: .sp .ne 2 .na \fB\fBELOOP\fR\fR .ad .RS 16n Too many symbolic links were encountered in resolving \fIpath\fR. .RE .sp .ne 2 .na \fB\fBENAMETOOLONG\fR\fR .ad .RS 16n The length of the \fIpath\fR argument exceeds {\fBPATH_MAX\fR} or a pathname component is longer than {\fBNAME_MAX\fR}. .RE .SH EXAMPLES \fBExample 1 \fRCreate a FIFO File .sp .LP The following example demonstrates how to create a FIFO file named \fB/home/cnd/mod_done\fR with read and write permissions for the owner and read permissions for the group and others. .sp .in +2 .nf #include #include int status; \&... status = mkfifo("/home/cnd/mod_done", S_IWUSR | S_IRUSR | S_IRGRP | S_IROTH); .fi .in -2 .SH ATTRIBUTES See \fBattributes\fR(7) for descriptions of the following attributes: .sp .sp .TS box; c | c l | l . ATTRIBUTE TYPE ATTRIBUTE VALUE _ Interface Stability Standard _ MT-Level MT-Safe .TE .SH SEE ALSO .BR mkdir (1), .BR chmod (2), .BR exec (2), .BR mknod (2), .BR umask (2), .BR stat.h (3HEAD), .BR ufs (4FS), .BR attributes (7), .BR standards (7)