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libc/uio: enable writev() for sockets

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spiriou 2020-09-21 11:37:48 +02:00 committed by Xiang Xiao
parent 65bb956e5e
commit a1c047fe53
1 changed files with 14 additions and 13 deletions
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27
libs/libc/uio/lib_writev.c
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@ -52,9 +52,10 @@
* 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.
* 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
@ -98,10 +99,6 @@ ssize_t writev(int fildes, FAR const struct iovec *iov, int iovcnt)
/* Get the current file position in case we have to reset it */
pos = lseek(fildes, 0, SEEK_CUR);
if (pos == (off_t)-1)
{
return ERROR;
}
/* Process each entry in the struct iovec array */
@ -126,17 +123,21 @@ ssize_t writev(int fildes, FAR const struct iovec *iov, int iovcnt)
if (nwritten < 0)
{
/* Save the errno value */
if (pos != (off_t)-1)
{
/* Save the errno value */
int save = get_errno();
int save = get_errno();
/* Restore the file position */
/* Restore the file position */
lseek(fildes, pos, SEEK_SET);
lseek(fildes, pos, SEEK_SET);
/* Restore the errno value */
/* Restore the errno value */
set_errno(save);
}
set_errno(save);
return ERROR;
}