Receives and outputs standard output of Python 2 and Python 3> C implementations

Raspberry Pi 2 Model B (Below RPi)
Raspbian Jessie
Python 2.7.9
Python 3.4.2
gcc (Raspbian 4.9.2-10) 4.9.2

Overview

--Standard output every second with C implementation --Receive the standard output and output it as standard in Python

I am planning to implement I2C communication in C and send the result to RS-232C in Python using pySerial. Preliminary investigation for that.

Implementation

C> Standard output every 1 second

-Raspberry Pi> C> Get up to msec (milliseconds) of local time and output standard> gettimeofday () used version and clock_gettime () used version

tickTime_180801.c

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdint.h>
#include <time.h>

static void printTime_clock_gettime(bool addLF)
{
    struct timespec tvToday; // for msec
    struct tm *ptm; // for date and time

    clock_gettime(CLOCK_REALTIME_COARSE, &tvToday);
    ptm = localtime(&tvToday.tv_sec);

    // date and time
    printf("%04d/%02d/%02d,%02d:%02d:%02d,",
        ptm->tm_year + 1900, ptm->tm_mon + 1, ptm->tm_mday,
        ptm->tm_hour, ptm->tm_min, ptm->tm_sec);
    // msec
    printf("%03d,", (uint16_t)(tvToday.tv_nsec / 1000000));

    if (addLF) {
        printf("\n");
    }
}

int main(void)
{
	struct timespec req;	
	int loop;
	
	req.tv_sec = 1;
	req.tv_nsec = 0;

	for(loop=0; loop<5; loop++) {
		printTime_clock_gettime(/*addLF=*/true);
		fflush(stdout);
		nanosleep(&req, NULL);
	}
}

Python 2> Receives standard output and outputs standard output

redirect_180801.py

# v0.1 Aug. 01, 2018
#   - break when [EOFError]
#   - read using raw_input()

# on Python 2.7.9

while True:
    try:
        res = raw_input()
        print(res)
    except EOFError:
        break

Compile and run

-python> print> Redirected only at the end of processing?> Execute with -u

python

$ gcc tickTime_180801.c -o tickTime_180801
$ ./tickTime_180801 | python2 -u redirect_180801.py 
2018/08/01,18:06:11,972,
2018/08/01,18:06:12,982,
2018/08/01,18:06:13,982,
2018/08/01,18:06:14,982,
2018/08/01,18:06:15,982,

Standard output is performed every second.

** Note: raw_input () is used in Python 2 **

Remarks

--sys.stdin did not work as expected

Python 3> Receives standard output and outputs standard output

Python 3 uses input () instead of raw_input ().

--Reference: Introduction to Python for Science and Technology Calculation by Kenji Nakaku --Table 1.4 on p14 Example of differences between Python 2 series and Python 3 series

redirect_py3_180801.py

# v0.1 Aug. 01, 2018
#   - break when [EOFError]
#   - read using raw_input()

# on Python 3.4.2

while True:
    try:
        res = input()
        print(res)
    except EOFError:
        break

run

$ ./tickTime_180801 | python3 -u redirect_py3_180801.py 
2018/08/01,18:37:13,143,
2018/08/01,18:37:14,153,
2018/08/01,18:37:15,153,
2018/08/01,18:37:16,153,
2018/08/01,18:37:17,163,