Operating System – Water's Home

Calling a C Function From Lua

Posted on August 16, 2019 by admin

Prepare So

```
#include <math.h>
```
```
#include <lua.h>
```
```
#include <lauxlib.h>
```
```
#include <lualib.h>
```
```
 
```
```
static int my_sum(lua_State *L){
```
```
    int d1 = luaL_checknumber(L, 1);
```
```
    int d2 = luaL_checknumber(L, 2);
```
```
    lua_pushnumber(L, d1+d2);
```
```
    return 1;
```
```
}
```
```
 
```
```
static int my_info(lua_State *L){
```
```
    lua_pushstring(L, "qinuu");
```
```
    return 1;
```
```
}
```
```
 
```

static const struct luaL_Reg test_lib[] = {

```
    {"my_sum" , my_sum},
```
```
    {"my_info" , my_info},
```
```
    {NULL, NULL}
```
```
};
```
```
 
```
```
int luaopen_test_lib(lua_State *L){
```
```
    //luaL_newlib(L, test_lib); // 5.2
```

    luaL_register(L, "test_lib",test_lib); // lua 5.1

```
    return 1;
```
```
}
```

Test

```
local my_lib = require "test_lib"
```
```
 
```
```
print(type(test_lib))
```
```
 
```
```
print(test_lib.my_sum(23,17))
```
```
 
```
```
print(test_lib.my_info())
```

How to Connect Internal and External Networks at the same time : Windows

Posted on August 16, 2019 by admin

Delete Default Route

route delete 0.0.0.0

Add Gateway : Internal

route add 192.168.10.0 mask 255.255.255.0 192.168.10.1 -p

Add Gateway : External

route add 0.0.0.0 mask 0.0.0.0 192.168.20.1 -p

Check It!

route print
IPv4 Route Table
===========================================================================
Active Routes:
Network Destination Netmask Gateway Interface Metric
0.0.0.0 0.0.0.0 192.168.20.254 192.168.20.151 55
0.0.0.0 0.0.0.0 192.168.1.1 192.168.1.103 45

===========================================================================
Persistent Routes:
Network Address Netmask Gateway Address Metric
192.168.1.0 255.255.255.0 192.168.1.1 1
192.168.3.0 255.255.255.0 192.168.3.1 1

Profile : Linux -> PNG

Posted on July 11, 2019 by admin

gprof -b emv_clc2 > report.txt gprof2dot.py report.txt > call_graph.dot dot -Tpng call_graph.dot -o call_graph.png

1>LINK : fatal error LNK1104: cannot open file ‘libboost_date_time-vc142-mt-s-x32-1_70.lib’

Posted on June 28, 2019 by admin

C:\boost_1_70_0>.\b2 --with-date_time link=static runtime-link=static

Speed up by ignoring std::cout

Posted on May 21, 2019 by admin

Test Code

```
#include <iostream>
```
```
 
```
```
int main(int argc, char *argv[])
```
```
{
```

	//std::cout.setstate(std::ios_base::badbit);

```
	for(int i = 0; i < 100; i ++) {
```
```
		for(int i = 0; i < 100; i ++) {
```
```
			;//std::cout << "" << std::endl;
```
```
		}
```
```
	}
```
```
	return 0;
```
```
}
```

Test it without std::cout

```
root@imx6ul7d:~/tmp# time ./t1_1 
```
```
 
```
```
real    0m0.041s
```
```
user    0m0.020s
```
```
sys     0m0.000s
```

Test it with std::cout, but redirect to /dev/null

root@imx6ul7d:~/tmp# time ./t1_0 > /dev/null

```
 
```
```
real    0m0.096s
```
```
user    0m0.030s
```
```
sys     0m0.030s
```

Test it with std::cout, but set io state

```
root@imx6ul7d:~/tmp# time ./t1_2
```
```
 
```
```
real    0m0.061s
```
```
user    0m0.040s
```
```
sys     0m0.000s
```

Profile : Linux

Posted on May 17, 2019 by admin

Example 1

Add -pg

arm-linux-gnueabihf-g++ -Wall -g -pg hello.cpp -o hello -std=c++17

Test

```
root@imx6ul7d:~# gprof -b hello 
```
```
Flat profile:
```
```
 
```
```
Each sample counts as 0.01 seconds.
```

  %   cumulative   self              self     total

 time   seconds   seconds    calls   s/call   s/call  name

100.00      3.45     3.45        1     3.45     3.45  hehe()

  0.00      3.45     0.00        4     0.00     0.00  std::_Optional_base<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >::_M_is_engaged() const

```
......
```

First Line of Code (Version 2) Notes

Posted on May 6, 2019 by admin

Routes stream to specified buffer

Posted on April 10, 2019 by admin

Developer Command Prompt for VS 2019

```
cl basic_ios_rdbuf.cpp /EHsc
```

MSDN Source Code

```
#include <ios>
```
```
#include <iostream>
```
```
#include <fstream>
```
```
 
```
```
int main( ) 
```
```
{
```
```
   using namespace std;
```
```
   ofstream file( "rdbuf.txt" );
```

   streambuf *x = cout.rdbuf( file.rdbuf( ) );

   cout << "test" << endl; // Goes to file

```
   cout.rdbuf(x);
```
```
   cout << "test2" << endl; //normal
```
```
}
```

IPC Performance : Socket on ARM

Posted on April 10, 2019April 10, 2019 by admin

Test Environment

CPU: Freescale i.MX6UL rev1.1 528 MHz
DRAM: 512 MiB

Test Code

```
#include <stdlib.h>
```
```
#include <sys/types.h>
```
```
#include <sys/socket.h> 
```
```
#include <netinet/in.h>
```
```
#include <errno.h>
```
```
#include <string.h>
```
```
#include <unistd.h>
```
```
#include <fcntl.h>
```
```
 
```
```
#define CLTIP "127.0.0.1"
```
```
#define SRVPORT 10172
```
```
#define MAX_NUM 1024
```
```
 
```
```
int main(int argc, char* argv[])
```
```
{
```
```
	struct timeval tv_sta, tv_end;
```
```
 
```
```
	gettimeofday(&tv_sta, NULL);
```
```
 
```
```
	int i = 0;
```
```
	int total = 1;
```
```
	int is_printf = 1;
```
```
	if (argc > 1) {
```
```
		total = atoi(argv[1]);
```
```
	}
```
```
	if (argc > 2) {
```
```
		is_printf = atoi(argv[2]);
```
```
	}
```
```
 
```
```
	for (i = 0; i < total; i++) {
```
```
 
```

		int clientsock = socket(PF_INET, SOCK_STREAM, 0);

```
		if (clientsock < 0)
```
```
		{
```
```
			printf("socket creation failed\n");
```
```
			exit(-1);
```
```
		}
```
```
		if (is_printf)
```

			printf("socket create successfully.\n");

```
 
```
```
		struct sockaddr_in clientAddr;
```
```
		clientAddr.sin_family = AF_INET;
```

		clientAddr.sin_port = htons((u_short)SRVPORT);

		clientAddr.sin_addr.s_addr = inet_addr(CLTIP);

```
 
```

		int flags = fcntl(clientsock, F_GETFL, 0);

		fcntl(clientsock, F_SETFL, flags | O_NONBLOCK);

```
 
```
```
		int n;
```

		if ((n = connect(clientsock, (struct sockaddr*) & clientAddr, sizeof(struct sockaddr))) < 0)

```
		{
```
```
			if (errno != EINPROGRESS) {
```

				printf("Connect error.IP[%s], port[%d]\n", CLTIP, clientAddr.sin_port);

```
				exit(-1);
```
```
			}
```
```
		}
```
```
 
```
```
		if (n != 0) {
```
```
 
```
```
			fd_set rset, wset;
```
```
			FD_ZERO(&rset);
```
```
			FD_SET(clientsock, &rset);
```
```
			wset = rset;
```
```
			struct timeval tval;
```
```
			tval.tv_sec = 1;
```
```
			tval.tv_usec = 0;
```

			if ((n = select(clientsock + 1, &rset, &wset, NULL, 3 ? &tval : NULL)) == 0) {

				printf("Connect TIMEOUT.IP[%s], port[%d]\n", CLTIP, clientAddr.sin_port);

```
				exit(-1);
```
```
			}
```

			if (FD_ISSET(clientsock, &rset) || FD_ISSET(clientsock, &wset)) {

```
				int error;
```
```
				int len = sizeof(error);
```

				if (getsockopt(clientsock, SOL_SOCKET, SO_ERROR, &error, &len) < 0) {

```
					printf("pending error");
```
```
					exit(-1);
```
```
				}
```
```
			}
```
```
			else {
```

				printf("select error: clientsock not set");

```
				exit(-1);
```
```
			}
```
```
 
```
```
		}
```
```
		fcntl(clientsock, F_SETFL, flags);
```
```
 
```
```
		if (is_printf)
```

			printf("Connect to IP[%s], port[%d]\n", CLTIP, clientAddr.sin_port);

```
 
```

		const char* sendBuf = "{\"signalType\":\"CONFIG\", \"signalData\":[{\"id\":\"CONF_NAME\", \"value\":\"PPS_MChip1\"}]}";

```
		char recvBuf[MAX_NUM] = { 0 };
```
```
 
```
```
		//while(gets(sendBuf) != '\0')
```
```
		{
```

			if (send(clientsock, sendBuf, strlen(sendBuf), 0) == -1)

```
			{
```
```
				printf("send error!\n");
```
```
			}
```
```
			if (is_printf)
```

				printf("send to server:%s\n", sendBuf);

			//memset(sendBuf, 0, sizeof(sendBuf));

```
 
```
```
			{
```
```
				int timeOut = 3000;
```
```
				int nRet = 0;
```
```
				struct timeval timeout;
```
```
				fd_set recvset;
```
```
				FD_ZERO(&recvset);
```
```
				FD_SET(clientsock, &recvset);
```
```
				timeout.tv_sec = timeOut / 1000;
```
```
				timeout.tv_usec = timeOut % 1000;
```

				nRet = select(clientsock + 1, &recvset, 0, 0, &timeout);

```
				if (nRet <= 0)
```
```
				{
```

					printf("clientsock recv select is error!\n");

```
					exit(-1);
```
```
				}
```
```
			}
```
```
 
```

			if (recv(clientsock, recvBuf, MAX_NUM, 0) == -1)

```
			{
```
```
				printf("rev error!\n");
```
```
			}
```
```
			if (is_printf)
```

				printf("receive from server:%s\n", recvBuf);

			if (strcmp(recvBuf, "Goodbye,my dear client!") == 0)

```
			{
```
```
				//break;
```
```
			}
```
```
			memset(recvBuf, 0, sizeof(recvBuf));
```
```
		}
```
```
		close(clientsock);
```
```
 
```
```
	}
```
```
 
```
```
	gettimeofday(&tv_end, NULL);
```
```
 
```

	int total_millisecond = (tv_end.tv_sec * 1000 + tv_end.tv_usec / 1000) - (tv_sta.tv_sec * 1000 + tv_sta.tv_usec / 1000);

	int average_millisecond = (total_millisecond / total);

```
 
```

	printf("total_millisecond : %ld total_nums : %d\n", total_millisecond, total);

	printf("average_millisecond   : %ld\n", average_millisecond);

```
 
```
```
	return 0;
```
```
}
```

Test Result

```
root@imx6ul7d:~/tmp# ./a.out 1 0
```
```
total_millisecond : 13 total_nums : 1
```
```
average_millisecond   : 13
```
```
root@imx6ul7d:~/tmp# ./a.out 10 0
```
```
total_millisecond : 104 total_nums : 10
```
```
average_millisecond   : 10
```
```
root@imx6ul7d:~/tmp# ./a.out 100 0 
```

total_millisecond : 1023 total_nums : 100

```
average_millisecond   : 10
```
```
root@imx6ul7d:~/tmp# ./a.out 1000 0
```

total_millisecond : 10801 total_nums : 1000

Category: Operating System

Calling a C Function From Lua

Prepare So

Test

How to Connect Internal and External Networks at the same time : Windows

Delete Default Route

Add Gateway : Internal

Add Gateway : External

Check It!

Profile : Linux -> PNG

1>LINK : fatal error LNK1104: cannot open file ‘libboost_date_time-vc142-mt-s-x32-1_70.lib’

Speed up by ignoring std::cout

Test Code

Test it without std::cout

root@imx6ul7d:~/tmp# time ./t1_1

real 0m0.041s
user 0m0.020s
sys 0m0.000s

Test it with std::cout, but redirect to /dev/null

root@imx6ul7d:~/tmp# time ./t1_0 > /dev/null

real 0m0.096s
user 0m0.030s
sys 0m0.030s

Test it with std::cout, but set io state

root@imx6ul7d:~/tmp# time ./t1_2

real 0m0.061s
user 0m0.040s
sys 0m0.000s

Profile : Linux

Example 1

Add -pg

arm-linux-gnueabihf-g++ -Wall -g -pg hello.cpp -o hello -std=c++17

First Line of Code (Version 2) Notes

Routes stream to specified buffer

Developer Command Prompt for VS 2019

MSDN Source Code

IPC Performance : Socket on ARM

Test Environment

Test Code

Test Result

Upgrade to Visual Studio 2019 : Build Problems

1. std::toupper —> ::toupper

Original Code (It’s OKay in VS2017) :

VS Upgraded :

Code Updated (It’s OKay in VS2019) :

Prepare So

Test

Delete Default Route

Add Gateway : Internal

Add Gateway : External

Check It!

Test Code

Test it without std::cout root@imx6ul7d:~/tmp# time ./t1_1 real 0m0.041suser 0m0.020ssys 0m0.000s

Test it with std::cout, but redirect to /dev/null root@imx6ul7d:~/tmp# time ./t1_0 > /dev/null real 0m0.096suser 0m0.030ssys 0m0.030s

Test it with std::cout, but set io state root@imx6ul7d:~/tmp# time ./t1_2 real 0m0.061suser 0m0.040ssys 0m0.000s

Example 1

Add -pg arm-linux-gnueabihf-g++ -Wall -g -pg hello.cpp -o hello -std=c++17

Developer Command Prompt for VS 2019

MSDN Source Code

Test Environment

Test Code

Test Result

1. std::toupper —> ::toupper

Original Code (It’s OKay in VS2017) :

VS Upgraded :

Code Updated (It’s OKay in VS2019) :

Test it without std::cout

root@imx6ul7d:~/tmp# time ./t1_1

real 0m0.041s
user 0m0.020s
sys 0m0.000s

Test it with std::cout, but redirect to /dev/null

root@imx6ul7d:~/tmp# time ./t1_0 > /dev/null

real 0m0.096s
user 0m0.030s
sys 0m0.030s

Test it with std::cout, but set io state

root@imx6ul7d:~/tmp# time ./t1_2

real 0m0.061s
user 0m0.040s
sys 0m0.000s

Add -pg

arm-linux-gnueabihf-g++ -Wall -g -pg hello.cpp -o hello -std=c++17