@comment The start of a function description is indicated by the following
@comment comment. This syntax is used by the script functxh.sh:
@comment @comment function <name>

@comment function readv

@node readv, io
@findex readv

@subheading Syntax

@example
#include <sys/uio.h>

ssize_t readv (int fd, const struct iovec *iov, int iovcnt);
@end example

@subheading Description

@code{readv()} performs a scatter-gather read from the specified file
descriptor @var{fd}.  The data is written into a group of buffers described
by the array @var{iov} with @var{iovcnt} entries in a similar way to
@code{read()} (@pxref{read, , read, libc}).

@code{struct iovec} is described in the section on @code{writev()}
(@pxref{writev}).

@subheading Return Value

On successful completion the function returns the number of bytes read.
Otherwise, a value of -1 is returned and @var{errno} is set appropriately.

@table @samp

@item EINVAL
One of the following conditions is true:

@itemize @bullet
@item
The total length to read could overflow a @samp{ssize_t}.
@item
@var{iovcnt} was negative, zero or larger than @code{IOV_MAX}.
@end itemize

@end table

@subheading Portability

@portability posix, unix98

@subheading Example

@example
@end example