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| .TH MKFIFO 3 1995-09-03 "Linux 1.2.13" "Linux Programmer's Manual" |
| .SH NAME |
| mkfifo \- make a FIFO special file (a named pipe) |
| .SH SYNOPSIS |
| .nf |
| .B #include <sys/types.h> |
| .B #include <sys/stat.h> |
| .sp |
| .BI "int mkfifo(const char *" pathname ", mode_t " mode ); |
| .fi |
| .SH DESCRIPTION |
| \fBmkfifo\fP() makes a FIFO special file with name \fIpathname\fP. |
| \fImode\fP specifies the FIFO's permissions. It is modified by the |
| process's \fBumask\fP in the usual way: the permissions of the created |
| file are \fB(\fP\fImode\fP\fB & ~umask)\fP. |
| .PP |
| 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 \fBmkfifo\fP(). |
| .PP |
| 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 |
| .BR fifo (4) |
| for non-blocking handling of FIFO special files. |
| .SH "RETURN VALUE" |
| On success \fImkfifo\fP() returns 0. In |
| the case of an error, -1 is returned (in which case, \fIerrno\fP |
| is set appropriately). |
| .SH ERRORS |
| .TP |
| .B EACCES |
| One of the directories in \fIpathname\fP did not allow search |
| (execute) permission. |
| .TP |
| .B EEXIST |
| \fIpathname\fP already exists. |
| .TP |
| .B ENAMETOOLONG |
| Either the total length of \fIpathname\fP is greater than |
| \fBPATH_MAX\fP, or an individual file name component has a length |
| greater than \fBNAME_MAX\fP. 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. |
| .TP |
| .B ENOENT |
| A directory component in \fIpathname\fP does not exist or is a |
| dangling symbolic link. |
| .TP |
| .B ENOSPC |
| The directory or filesystem has no room for the new file. |
| .TP |
| .B ENOTDIR |
| A component used as a directory in \fIpathname\fP is not, in fact, a |
| directory. |
| .TP |
| .B EROFS |
| \fIpathname\fP refers to a read-only filesystem. |
| .SH "CONFORMING TO" |
| POSIX.1 |
| .SH "SEE ALSO" |
| .BR mkfifo (1), |
| .BR close (2), |
| .BR open (2), |
| .BR read (2), |
| .BR stat (2), |
| .BR umask (2), |
| .BR write (2), |
| .BR fifo (4) |