Trivial updates from review of vecto I/O logic.

This commit is contained in:
Gregory Nutt
2018-06-23 09:01:42 -06:00
parent 706a6a2c19
commit 5db2f993f9
5 changed files with 76 additions and 33 deletions
+15 -8
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@@ -1,7 +1,7 @@
/****************************************************************************
* libs/libc/stdio/lib_readv.c
*
* Copyright (C) 2017 Gregory Nutt. All rights reserved.
* Copyright (C) 2017=-2018 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
@@ -50,17 +50,17 @@
*
* 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.
* 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.
*
* Upon successful completion, readv() will mark for update the st_atime
* field of the file.
* 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
@@ -70,7 +70,14 @@
* 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().
* 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).
*
****************************************************************************/
+13 -7
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@@ -1,7 +1,7 @@
/****************************************************************************
* libs/libc/stdio/lib_writev.c
*
* Copyright (C) 2017 Gregory Nutt. All rights reserved.
* Copyright (C) 2017-2018 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
@@ -51,20 +51,20 @@
*
* 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
* 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 fildes refers to a regular file and all of the iov_len members in
* 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.
*
* If the sum of the iov_len values is greater than SSIZE_MAX, the
* 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:
@@ -76,7 +76,13 @@
* 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.
* 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).
*
****************************************************************************/