incubator-nuttx/libs/libc/misc/lib_mkfifo.c

83 lines
2.9 KiB
C

/****************************************************************************
* libs/libc/misc/lib_mkfifo.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <nuttx/fs/fs.h>
#if defined(CONFIG_PIPES) && CONFIG_DEV_FIFO_SIZE > 0
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: mkfifo
*
* Description:
* mkfifo() makes a FIFO device driver file with name 'pathname.' Unlike
* Linux, a NuttX FIFO is not a special file type but simply a device
* driver instance. 'mode' specifies the FIFO's permissions.
*
* Once the FIFO has been created by mkfifo(), any thread can open it for
* reading or writing, in the same way as an ordinary file. However, it
* must have been opened from both reading and writing before input or
* output can be performed. This FIFO implementation will block all
* attempts to open a FIFO read-only until at least one thread has opened
* the FIFO for writing.
*
* If all threads that write to the FIFO have closed, subsequent calls to
* read() on the FIFO will return 0 (end-of-file).
*
* Input Parameters:
* pathname - The full path to the FIFO instance to attach to or to create
* (if not already created).
* mode - Ignored for now
*
* Returned Value:
* 0 is returned on success; otherwise, -1 is returned with errno set
* appropriately.
*
****************************************************************************/
int mkfifo(FAR const char *pathname, mode_t mode)
{
int ret;
ret = nx_mkfifo(pathname, mode, CONFIG_DEV_FIFO_SIZE);
if (ret < 0)
{
set_errno(-ret);
ret = ERROR;
}
return ret;
}
#endif /* CONFIG_PIPES && CONFIG_DEV_FIFO_SIZE > 0 */