/*********************************************************************************
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* Copyright: (C) 2021 LingYun IoT System Studio
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* All rights reserved.
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*
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* Filename: led.c
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* Description: This file is used to control RGB 3-colors LED
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*
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*
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* Pin connection:
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* RGB Led Module Raspberry Pi Board
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* R <-----> #Pin33(BCM GPIO13)
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* G <-----> #Pin35(BCM GPIO19)
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* B <-----> #Pin37(BCM GPIO26)
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* GND <-----> GND
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*
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* System install:
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* sudo apt install -y libgpiod-dev gpiod
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*
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*
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********************************************************************************/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <dirent.h>
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#include <string.h>
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#include <time.h>
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#include <errno.h>
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#include <signal.h>
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#include <gpiod.h>
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#define DELAY 500
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#define ON 1
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#define OFF 0
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/* Three LEDs code */
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enum
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{
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LED_R = 0,
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LED_G,
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LED_B,
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LEDCNT,
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};
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/* Three LEDs hardware information */
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typedef struct led_info_s
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{
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const char *name; /* RGB 3-color LED name */
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int gpio; /* RGB 3-color LED BCM pin number */
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int active;/* RGB 3-color LED active GPIO level: 0->low 1->high */
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struct gpiod_line *line; /* libgpiod line */
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} led_info_t;
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static led_info_t leds_info[LEDCNT] =
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{
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{"red", 13, 1, NULL },
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{"green", 19, 1, NULL },
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{"blue", 26, 1, NULL },
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};
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/* Three LEDs API context */
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typedef struct led_ctx_s
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{
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struct gpiod_chip *chip;
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led_info_t *leds;
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int count;
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} led_ctx_t;
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int init_led(led_ctx_t *ctx);
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int term_led(led_ctx_t *ctx);
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int turn_led(led_ctx_t *ctx, int which, int cmd);
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static inline void msleep(unsigned long ms);
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int g_stop = 0;
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void sig_handler(int signum)
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{
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switch( signum )
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{
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case SIGINT:
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case SIGTERM:
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g_stop = 1;
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default:
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break;
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}
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return ;
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}
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int main(int argc, char *argv[])
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{
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int rv;
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led_ctx_t led_ctx =
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{
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.chip = NULL,
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.leds = leds_info,
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.count = LEDCNT,
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};
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if( (rv=init_led(&led_ctx)) < 0 )
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{
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printf("initial leds gpio failure, rv=%d\n", rv);
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return 1;
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}
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printf("initial RGB Led gpios okay\n");
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signal(SIGINT, sig_handler);
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signal(SIGTERM, sig_handler);
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while( !g_stop )
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{
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turn_led(&led_ctx, LED_R, ON);
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msleep(DELAY);
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turn_led(&led_ctx, LED_R, OFF);
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msleep(DELAY);
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turn_led(&led_ctx, LED_G, ON);
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msleep(DELAY);
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turn_led(&led_ctx, LED_G, OFF);
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msleep(DELAY);
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turn_led(&led_ctx, LED_B, ON);
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msleep(DELAY);
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turn_led(&led_ctx, LED_B, OFF);
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msleep(DELAY);
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}
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term_led(&led_ctx);
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return 0;
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}
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int term_led(led_ctx_t *ctx)
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{
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int i;
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led_info_t *led;
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printf("terminate RGB Led gpios\n");
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if( !ctx )
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{
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printf("Invalid input arguments\n");
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return -1;
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}
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if( !ctx->chip )
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return 0;
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for(i=0; i<ctx->count; i++)
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{
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led = &ctx->leds[i];
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if( led->line )
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gpiod_line_release(led->line);
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}
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gpiod_chip_close(ctx->chip);
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return 0;
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}
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int init_led(led_ctx_t *ctx)
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{
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int i, rv;
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led_info_t *led;
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if( !ctx )
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{
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printf("Invalid input arguments\n");
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return -1;
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}
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ctx->chip = gpiod_chip_open_by_name("gpiochip0");
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if( !ctx->chip )
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{
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printf("open gpiochip failure, maybe you need running as root\n");
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return -2;
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}
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for(i=0; i<ctx->count; i++)
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{
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led = &ctx->leds[i];
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led->line = gpiod_chip_get_line(ctx->chip, led->gpio);
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if( !led->line )
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{
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printf("open gpioline for %s[%d] failed\n", led->name, led->gpio);
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rv = -3;
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goto failed;
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}
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rv = gpiod_line_request_output(led->line, led->name, !led->active);
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if( rv )
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{
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printf("request gpio output for %5s[%d] failed\n", led->name, led->gpio);
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rv = -4;
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goto failed;
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}
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//printf("request %5s led[%d] for gpio output okay\n", led->name, led->gpio);
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}
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return 0;
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failed:
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term_led(ctx);
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return rv;
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}
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int turn_led(led_ctx_t *ctx, int which, int cmd)
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{
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int rv = 0;
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led_info_t *led;
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if( !ctx || which<0 || which>=ctx->count )
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{
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printf("Invalid input arguments\n");
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return -1;
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}
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led = &ctx->leds[which];
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if( OFF == cmd )
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{
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gpiod_line_set_value(led->line, !led->active);
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}
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else
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{
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gpiod_line_set_value(led->line, led->active);
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}
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return 0;
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}
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static inline void msleep(unsigned long ms)
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{
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struct timespec cSleep;
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unsigned long ulTmp;
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cSleep.tv_sec = ms / 1000;
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if (cSleep.tv_sec == 0)
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{
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ulTmp = ms * 10000;
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cSleep.tv_nsec = ulTmp * 100;
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}
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else
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{
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cSleep.tv_nsec = 0;
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}
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nanosleep(&cSleep, 0);
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return ;
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}
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