zephyr/lib/posix/sleep.c
Chris Friedt 7b95428fa0 lib: posix: update usleep() to follow the POSIX spec
The original implementation of `usleep()` was not compliant
to the POSIX spec in 3 ways.
- calling thread may not be suspended (because `k_busy_wait()`
  was previously used for short durations)
- if `usecs` > 1000000, previously we did not return -1 or set
  `errno` to `EINVAL`
- if interrupted, previously we did not return -1 or set
  `errno` to `EINTR`

This change addresses those issues to make `usleep()` more
POSIX-compliant.

Signed-off-by: Chris Friedt <cfriedt@meta.com>
2022-11-24 19:31:33 -05:00

50 lines
771 B
C

/*
* Copyright (c) 2018 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <errno.h>
#include <zephyr/kernel.h>
#include <zephyr/posix/unistd.h>
/**
* @brief Sleep for a specified number of seconds.
*
* See IEEE 1003.1
*/
unsigned sleep(unsigned int seconds)
{
int rem;
rem = k_sleep(K_SECONDS(seconds));
__ASSERT_NO_MSG(rem >= 0);
return rem / MSEC_PER_SEC;
}
/**
* @brief Suspend execution for microsecond intervals.
*
* See IEEE 1003.1
*/
int usleep(useconds_t useconds)
{
int32_t rem;
if (useconds >= USEC_PER_SEC) {
errno = EINVAL;
return -1;
}
rem = k_usleep(useconds);
__ASSERT_NO_MSG(rem >= 0);
if (rem > 0) {
/* sleep was interrupted by a call to k_wakeup() */
errno = EINTR;
return -1;
}
return 0;
}