nuttx/include/sys/sendfile.h
2014-04-13 14:32:20 -06:00

124 lines
5.1 KiB
C

/****************************************************************************
* include/sys/sendfile.h
*
* Copyright (C) 2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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_SENDFILE_H
#define __INCLUDE_SYS_SENDFILE_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
/****************************************************************************
* Pre-Processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
#ifndef CONFIG_LIB_SENDFILE_BUFSIZE
# define CONFIG_LIB_SENDFILE_BUFSIZE 512
#endif
/****************************************************************************
* Public Type Definitions
****************************************************************************/
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
#undef EXTERN
#if defined(__cplusplus)
#define EXTERN extern "C"
extern "C" {
#else
#define EXTERN extern
#endif
/************************************************************************
* Name: sendfile
*
* Description:
* sendfile() copies data between one file descriptor and another.
* sendfile() basically just wraps a sequence of reads() and writes()
* to perform a copy. It serves a purpose in systems where there is
* a penalty for copies to between user and kernal space, but really
* nothing in NuttX but provide some Linux compatible (and adding
* another 'almost standard' interface).
*
* NOTE: This interface is *not* specified in POSIX.1-2001, or other
* standards. The implementation here is very similar to the Linux
* sendfile interface. Other UNIX systems implement sendfile() with
* different semantics and prototypes. sendfile() should not be used
* in portable programs.
*
* Input Parmeters:
* infd - A file (or socket) descriptor opened for reading
* outfd - A descriptor opened for writing.
* offset - If 'offset' is not NULL, then it points to a variable
* holding the file offset from which sendfile() will start
* reading data from 'infd'. When sendfile() returns, this
* variable will be set to the offset of the byte following
* the last byte that was read. If 'offset' is not NULL,
* then sendfile() does not modify the current file offset of
* 'infd'; otherwise the current file offset is adjusted to
* reflect the number of bytes read from 'infd.'
*
* If 'offset' is NULL, then data will be read from 'infd'
* starting at the current file offset, and the file offset
* will be updated by the call.
* count - The number of bytes to copy between the file descriptors.
*
* Returned Value:
* If the transfer was successful, the number of bytes written to outfd is
* returned. On error, -1 is returned, and errno is set appropriately.
* There error values are those returned by read() or write() plus:
*
* EINVAL - Bad input parameters.
* ENOMEM - Could not allocated an I/O buffer
*
************************************************************************/
ssize_t sendfile(int outfd, int infd, FAR off_t *offset, size_t count);
#undef EXTERN
#if defined(__cplusplus)
}
#endif
#endif /* __INCLUDE_SYS_SENDFILE_H */