ESP32 Forum

Posted: **Sat Oct 27, 2018 3:19 pm**

Hello,

I would like to use nanosleep() function but I got this error on compile:
error: implicit declaration of function 'nanosleep' [-Werror=implicit-function-declaration]
nanosleep(&tim , &tim2);
^

My code looks like this:

Code: Select all

#include "sdkconfig.h"
#include <stdio.h>
#include <time.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_system.h"
#include "esp_spi_flash.h"
#include "soc/cpu.h"
#include "esp_clk.h"

void app_main()
{
	int clock_freq = esp_clk_cpu_freq();
	printf("CPU Freq %d \n", clock_freq);
	struct timespec tim, tim2;
	tim.tv_sec =0;
	tim.tv_nsec = 500000000L;
	nanosleep(&tim , &tim2);
	fflush(stdout);
	esp_restart();
	return;
}

time.h is included and I am not sure ESP-IDF has an alternate.
Any help are welcome!

Regards,
Arpi

Posted: **Sun Oct 28, 2018 2:37 am**

Suggest you either use vTaskDelay (https://www.freertos.org/a00127.html) for large-ish delays (>20mS or so), and if you really need it, ets_delay_us for short ones. Note that if you need this to do bitbanging, you may be better off looking at the hardware peripherals we have, there's usually one that can do what you want in hardware.

Posted: **Mon Oct 29, 2018 2:24 am**

There's also 'usleep' which is a portable wrapper around ets_delay_us or vTaskDelay, depending on whether the delay is larger or smaller than the tick period. Thanks for the pointer about the missing nanosleep!

Posted: **Mon Oct 29, 2018 5:07 am**

For the time being I will try usleep.
RMT looks promising also. Thank you for your answers.

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