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Differential D26668 Diff 78030 lib/libc/gen/eventfd_rw.c

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lib/libc/gen/eventfd_rw.c

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/*-
* SPDX-License-Identifier: MIT
*
* Copyright (c) 2005-2020 Rich Felker, et al.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "namespace.h"
#include <sys/eventfd.h>
#include <unistd.h>
#include "un-namespace.h"
int eventfd_read(int fd, eventfd_t *value)
{
return (sizeof(*value) == _read(fd, value, sizeof(*value))) ? 0 : -1;
}
kibAuthorUnsubmitted
Not Done
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return (value);

Is errno supposed to contain a valid value when -1 is returned ? It is currently not.

kib: `return (value);` Is errno supposed to contain a valid value when -1 is returned ? It is…
val_packett.coolUnsubmitted
Done
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All the linux manpage says is

The GNU C library defines an additional type, and two functions that attempt to abstract some of the details of reading and writing on an eventfd file descriptor:

typedef uint64_t eventfd_t;

int eventfd_read(int fd, eventfd_t *value);
int eventfd_write(int fd, eventfd_t value);

The functions perform the read and write operations on an eventfd file descriptor, returning 0 if the correct number of bytes was transferred, or -1 otherwise.

Just like the musl implementation I took, the glibc implementation does not care about errno:
https://github.com/bminor/glibc/blob/master/sysdeps/unix/sysv/linux/eventfd_read.c

val_packett.cool: All the linux manpage says is > The GNU C library defines an additional type, and two…
int eventfd_write(int fd, eventfd_t value)
{
return (sizeof(value) == _write(fd, &value, sizeof(value))) ? 0 : -1;
}