156 lines
6.3 KiB
C
156 lines
6.3 KiB
C
/****************************************************************************
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* include/sys/uio.h
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*
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* Copyright (C) 2017 Grefory Nutt. All rights reserved.
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* Copyright (C) 2015 Stavros Polymenis. All rights reserved.
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* Author: Stavros Polymenis <sp@orbitalfox.com>
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* Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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#ifndef __INCLUDE_SYS_UIO_H
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#define __INCLUDE_SYS_UIO_H
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <sys/types.h>
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/****************************************************************************
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* Public Types
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****************************************************************************/
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struct iovec
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{
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FAR void *iov_base; /* Base address of I/O memory region */
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size_t iov_len; /* Size of the memory pointed to by iov_base */
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};
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/****************************************************************************
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* Public Function Prototypes
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****************************************************************************/
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#undef EXTERN
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#if defined(__cplusplus)
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#define EXTERN extern "C"
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extern "C"
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{
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#else
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#define EXTERN extern
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#endif
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/****************************************************************************
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* Name: readv()
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*
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* Description:
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* The readv() function is equivalent to read(), except as described below.
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* The readv() function places the input data into the 'iovcnt' buffers
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* specified by the members of the 'iov' array: iov[0], iov[1], ...,
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* iov['iovcnt'-1]. The 'iovcnt' argument is valid if greater than 0 and
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* less than or equal to IOV_MAX as defined in limits.h.
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*
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* Each iovec entry specifies the base address and length of an area in
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* memory where data should be placed. The readv() function will always
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* fill an area completely before proceeding to the next.
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*
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* TODO: pon successful completion, readv() will mark for update the
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* st_atime field of the file.
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*
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* Input Parameters:
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* filedes - The open file descriptor for the file to be read
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* iov - Array of read buffer descriptors
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* iovcnt - Number of elements in iov[]
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*
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* Returned Value:
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* Upon successful completion, readv() will return a non-negative integer
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* indicating the number of bytes actually read. Otherwise, the functions
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* will return -1 and set errno to indicate the error. See read() for the
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* list of returned errno values. In addition, the readv() function will
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* fail if:
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*
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* EINVAL.
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* The sum of the iov_len values in the iov array overflowed an ssize_t
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* or The 'iovcnt' argument was less than or equal to 0, or greater than
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* IOV_MAX (Not implemented).
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*
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****************************************************************************/
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ssize_t readv(int fildes, FAR const struct iovec *iov, int iovcnt);
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/****************************************************************************
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* Name: writev()
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*
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* Description:
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* The writev() function is equivalent to write(), except as described
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* below. The writev() function will gather output data from the 'iovcnt'
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* buffers specified by the members of the 'iov' array: iov[0], iov[1],
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* ..., iov[iovcnt-1]. The 'iovcnt' argument is valid if greater than 0
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* and less than or equal to IOV_MAX, as defined in limits.h.
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*
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* Each iovec entry specifies the base address and length of an area in
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* memory from which data should be written. The writev() function always
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* writes a complete area before proceeding to the next.
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*
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* If 'filedes' refers to a regular file and all of the iov_len members in
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* the array pointed to by iov are 0, writev() will return 0 and have no
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* other effect. For other file types, the behavior is unspecified.
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*
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* TODO: If the sum of the iov_len values is greater than SSIZE_MAX, the
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* operation will fail and no data will be transferred.
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*
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* Input Parameters:
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* filedes - The open file descriptor for the file to be read
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* iov - Array of read buffer descriptors
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* iovcnt - Number of elements in iov[]
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*
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* Returned Value:
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* Upon successful completion, writev() shall return the number of bytes
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* actually written. Otherwise, it shall return a value of -1, the file-
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* pointer shall remain unchanged, and errno shall be set to indicate an
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* error. See write for the list of returned errno values. In addition,
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* the readv() function will fail if:
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*
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* EINVAL.
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* The sum of the iov_len values in the iov array overflowed an ssize_t
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* or The 'iovcnt' argument was less than or equal to 0, or greater than
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* IOV_MAX (Not implemented).
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*
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****************************************************************************/
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ssize_t writev(int fildes, FAR const struct iovec *iov, int iovcnt);
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#undef EXTERN
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#if defined(__cplusplus)
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}
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#endif
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#endif /* __INCLUDE_SYS_UIO_H */
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