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