GisTips

How to use FeatureLayer in ArcGIS API for JavaScript 3.x

2019-09-20T12:16:00.001-07:00

In this post we will explain how to use FeatureLayer class in ArcGIS API for JavaScript.

applies to 3.x API

First we need to include (Map, FeatureLayer) classes from the API

require([
  "esri/map",
  "esri/layers/FeatureLayer",
  "dojo/ready",
], function(Map, FeatureLayer, ready) {

  ready(function(){
    // Put your code in this block.
  });
});

Also note that we used the ready class from dojo in order to run our code after the page is fully loaded.

Now we need to create a new object of type FeatureLayer. We do that in the "ready" function as follows:

ready(function(){
    var feature_layer = new FeatureLayer();
});

To properly creating an object of FeatureLayer, we need to pass some properties to its constructor

ready(function(){
  var feature_layer = new FeatureLayer(
    url_to_feature_layer
    , {
      mode: FeatureLayer.MODE_ONDEMAND,
      outFields: ["*"],
      visible: true,
      id: "id_inside_map"
    }
  );
});

Let us explain the properties:

url_to_feature_layer : The url of the FeatureLayer for example this is a URL from ESR:
https://services.arcgis.com/V6ZHFr6zdgNZuVG0/arcgis/rest/services/Prominent_Peaks_attach/FeatureServer/0
mode: The mode to load features:
MODE_ONDEMAND: Loads features when you pan to the extent in which they exist or when you zoom to the level in which the layer is visible.
MODE_SNAPSHOT: The features will be loaded once the layer is added to the map.
MODE_SELECTION: The feature will be loaded once it is selected using the "selectFeatures" method.
MODE_AUTO: The mode will be selected automatically depending on the number of features and the number of vertices in the features.
visible: Determines if the layer is visible in the map or not (the default value is true).
id: The ID of the layer in the map, this helps you to retrieve the layer from the map in a user friendly name.

Now we need to add the FeatureLayer to the map:

ready(function(){
  var feature_layer = new FeatureLayer(
    url_to_feature_layer
    , {
      mode: FeatureLayer.MODE_ONDEMAND,
      outFields: ["*"],
      visible: true,
      id: "id_inside_map"
    }
  );

 map.addLayer(feature_layer);

});

Thanks for reading my tutorial, please do not hesitate to ask any question in the comments.

تنصيب برنامج XAMPP

2019-05-29T08:55:00.000-07:00

بسم الله الرحمن الرحيم

سوف نقو بشرح مبسط لطريقة تنسيب برنامج XAMPP و هو عبارة عن حزمة تحتوي على سيرفر Apache و سيرفر MySQL و برنامج phpMyAdmin.

أولا نقوم بتنزيل البرنامج من موقعه الرسمي:

https://www.apachefriends.org/download.html

الآن نقوم بفتح البرنامج كمسؤول:

سوف تظهر الشاشة التالية:

نقوم بالضغط على زر Next لتظهر النافذة التالية:

من المربع رقم 1 نقوم باختيار الميزات التي نريد تنصيبها على الجهاز و في حالتنا هذه نريد فقط Apache و MySQL.

نضغط Next لتظهر الشاشة التالية:

في البند (1) نقوم باختيار مسار المجلد الذي نريد تنصيب البرنامج بداخله. سوف نترك القيمة الافتراضية كما هي.

ثم نضغط على زر Next لتظهر الشاشة التالية:

نقوم بإلغاء تفعل الخيار كما هو موضح في البند (1) و من ثم نضغط على زر Next لتظهر لنا الشاشة التالية:

سيتم الآن البدء بتنصيب XAMPP فقط اضغط على زر Next لتبدأ عملية التنصيب:

Create Geodatabase Version in ArcGIS and ArcMap

2019-05-21T22:29:00.001-07:00

To create a Geodatabsae Version we open ArcCatalog window from ArcMap and then go to our Enterprise Geodatabase Connection and right click on it and then choose as follows:

Administration --> Administer Geodatabase

As shown in the following image:

We will get the following window (Geodatabase Administration):

Then we choose the parent version for our new version, the version from which we will take a copy as follows:

Right click on parent version --> New Version

We will get the following window:

We fill the data according to the following brief explanation:

Name: The name of our new Version.
Description: general notes about the version.
Access: The access level of the version.

For Access level, please check this post:

ArcGIS Geodabase Version Access Level

ArcGIS Geodabase Version Access Level

2019-05-21T22:22:00.000-07:00

In this post we will explain the access level of geodatabase version.
The following table show in short and comprehensive way what each access level allows the owner of the version to do and what other users can do:

	Version Owner	Other Users
Public	View, Edit	View, Edit
Protected	View, Edit	View
Private	View, Edit	No Access

Create ArcGIS Enterprise Geodatabase in Oracle 11g R2

2019-05-10T01:09:00.003-07:00

In this tutorial I am going to explain in short and easy way how to create an enterprise geodatabase in Oracle 11g R2 with ArcMap.

First we need to have Oracle 11g R2 installed (click here for how to install oracle 11g R2).

After having Oracle 11g R2 installed, we will open the "Create Enterprise Geodatabase" tool from ArcCatalog window from the following path:

Toolboxes --> Data Management Tools --> Geodatabase Administration --> Create Enterprise Geodatabase

The tool will appear as in the following image:

The options are explained as following:

Database Platform : is the type of the database we are using, which in our case is Oracle.
Instance : the address to the database we are using.
Database Administrator Password : is the password of the user "SYS".
Geodatabase Administrator Password : the password of the user who is going to administer the whole geodatabase.
Authorization File : browse to select the keycodes file that you get from you installation of ArcGIS for Server. (How to Make a "keycodes" File)".

After setting all options, press "OK" (step 7) to start the process of creating a new enterprise geodatabase in Oracle 11g R2.

The tool will check if the "SYS" user has enough privileges to create the enterprise geodatabase or not as shown in the folling picture:

After that wait till the process finishes and you get the following screen:

Congratulations, you have just created a new enterprise geodatabase in Oracle 11g R2.

How to Resize Raspbian Image

2015-05-09T14:33:00.000-07:00

In this tutorial I am going to explain how te resize a raspbian image so it can be used in QEMU.
I faced the problem of having no space in to install extra packages on raspbian like Qt, so I decided to increase the space of the Raspbian image to 8 GB.
After a lost of search and testings, I discovered the best way to increase the size of raspbian to 8 GB or less or more. You can resize to any size, but make sure it is more than 3 GB; because Raspbian itself requires about 2.5 GB.

Caution: Please make a backup from the Raspbian raw file because we will need it at the end of this tutorial.

Step 1: Resizing the raw image file using QEMU.

# qemu-img resize +

For example:

# qemu-img resize 2015-02-16-raspbian-wheezy.img +5G

Note:
The 5G here will be added to the size of the original raw image. For example, raspbian image is 3 GBs and now it will become * GBs (3 GBs + 5 GBs).

Step 2: Resizing the root partition of Raspbian.

After first step you will notice that the root partition still 3 GBs; this because partition table of the raw image knows nothing about the change, since we only changed the raw file. So we need to do the following steps:

1- Associate the raw file of Raspbian image with a loop device.

# losetup -P

For example:

# losetup -P /dev/loop0 2015-02-16-raspbian-wheezy-8GB.img

2- Delete the root partition:

Note that the root partition number is 2.

# fdisk /dev/loop0
Now enter "d" and then enter "2"

3- Creating a new partition:

Note: Keep fdisk open and do the following:

1- Enter "p" to show the details of the current partitions. You will see only one small partition.

Note: We need the value inside the box witch is 122879 (It may vary from raspbian version to another)

2- Enter "n" and then enter "p" to select a primapry partition (p is the the default value).

3- Now enter the number of the partition. Enter "2" witch is the default option, or use the default option.

4- Now enter the beginning of the partition. We need the End value of the first partition from step 1 witch is in our case 122879. We add 1 to this value and the enter it to fdisk. Now the new partition will begin at 122880.

Note: if you used the default value for the beginning of the new partition, you will end up with a very small partition; because you will be allocating the free space before the first partition witch is very small and it is devoted for MBR and partition table, so you will also corrupt the raw image.

5- Choose the end of the new partition. Just leave the default vale.

6- Now we need to set the type of the new partition. Enter "t"

7- Enter the number of the partition for witch we will change type. In our case it is 2

8- Enter the number of the type of the file system. In our case it is 83.

9- Now enter "w" to write all changes to disk.

4- Update partition table that the kernel is using.

# partprobe

5- Format the newly create partition.

To get the path of the partition in dev folder, we use fdisk to print the partition table of the raw file

# fdisk /dev/loop0
Now Enter "p"

Notice the newly created partition is associated with /dev/loop0p2

To format the newly created partition

# mkfs.ext4 /dev/loop0p2

Now, we have a new partition that has no data inside it. We need o copy all files from the original Raspbian image to the new partition.
Note: We cannot use dd; because if we did, we will end up with a partition that is 3 GBs size and that is the size of the original partition in the Raspbian raw file.

We need to associate the original Raspbian raw file with a loop device

# losetup -P /dev/loop10 2015-02-16-raspbian-wheezy.img

Now mount both the newly created partition and the root partition from the original Raspbian raw file using any mount method that you prefer.
Then copy all folders and file in the rot partition of the original Raspbian raw file to the newly created partition without altering the permissions of files nor their owners.

# cp -rp /*

Foe example

# cp -rp /run/media/eng.mahmoud/f24a4949-f4b2-4cad-a780-a138695079ec/* /run/media/eng.mahmoud/6e001351-2aa9-4344-aa29-5ca8909a91da/

Congratulations, now you have your own resized Raspbian image.

Modelio refuse to start and complains about GTK+

2015-05-01T16:42:00.002-07:00

Modelio refuse to start and show me

Gtk-WARNING **: This process is currently running setuid or setgid.
This is not a supported use of GTK+. You must create a helper
program instead. For further details, see:

http://www.gtk.org/setuid.html

Refusing to initialize GTK+.

The solution was to re-install OpenJDK and if you are using Oracle Java, try to use OpenJDK instead.

Instaling and Configuring VNC Server on CentOS 7 and Fedora 20

2015-03-18T21:40:00.001-07:00

Introduction:

VNC Server gives you a good way and reliable way to run desktop environment on your server so you can have GUI control over your server just as you would use your local computer.
This tutorial is split into two parts, first installing VNC server, the second in configuring VNC server.

Why VNC:

More reliable than ssh graphics and RDP.
Using GUI tools to control your server.
Allows you to share clipboard between your local computer and the remote server.
You can use and host that have VNC client to control your server.

Note:

This tutorial was tested on both CentOS 7 and Fedora 20. If you encountered any problem, please leave a comment and I will help you get your problem solved.

Installing VNC Server:

You need to install the following in order to get VNC server up and running on you server:

Desktop Environment (XFCE, KDE, Gnome)
VNC Server.
Open ports in iptables to allow remote connections.

Now let us dive into the instructions

Installing your desktop environment:

XFCE
yum groupinstall xfce
Gnome
yum groupinstall "GNOME Desktop"

Installing VNC Server:

yum install tigervnc-server

Configuring VNC Server:
In this step we will configure VNC server in order to get it up and running and can pass iptables.

First we need to copy the template of the VNC server service file and put it on its real folder.

cp /lib/systemd/system/vncserver@.service /etc/systemd/system/vncserver@:1.service

We got the service file in its location, but it still not ready for actual usage.

Second we need to edit that file to properly configure it

vi /etc/systemd/system/vncserver@:1.service

Go to this section

[Service]
Type=forking
User=
ExecStart=/usr/bin/vncserver <:port_number> -geometry -depth 24
ExecStop=/usr/bin/vncserver -kill <:port_number>

and change it according to the following:

: Is the username that you like to login to when using VNC. For example engmah
<:port_number>: The port of the VNC service on which you will connect to. For example :2
: The default screen resolution that will be user, but in VNC client you can resize the screen dynamically without altering this value. For example: 1280x1024.

Here is an example:

[Service]
Type=forking
User=engmah
ExecStart=/usr/bin/vncserver :1 -geometry 1280x1024 -depth 24
ExecStop=/usr/bin/vncserver -kill :1

Thirdly we need to set up password for VNC.

Here the password is different from the password of the user that wil be logged in when using VNC. It is the password of the VNC session not the password of Linux user. So you can make it different than the password of the user.
To set VNC session password login to the user and execute:

vncpasswd

Then enter VNC session password. You will use this password when connecting to VNC server on the same port that you specified for the user in VNC service configuration file. For example we specified in the file the user engmah and the port is 2 so when connecting on port 2 we will be asked for the password for VNC session that is set via engmah user.

Now we need to run VNC server from the same user (e.g engmah)

vncserver

Finally we need to run the service:

Now login to root and execute the following commands

systemctl daemon-reload

systemctl enable vncserver@:1.service

systemctl start vncserver@:1.service

Here is an explanation for these three commands

systemctl daemon-reload

Is used to reload systemd so it recognizes your new service file

systemctl enable vncserver@:1.service

Enable your service to run at startup. Ti disable it from starting at startup use the following command

systemctl disable vncserver@:1.service

systemctl start vncserver@:1.service

Starts your service. If you want at anytime to stop your service use the following command

systemctl stop vncserver@:1.service

Note:
In the name of the service (i.e vncserver@:1.service) you noticed that we used @:1. The number we specify here is the number of the service port we specified in the configuration file of the service. This is useful because we can create many VNC services for many users, just create a new service file with a different port number and different username.

Extra things to do:

On some Linux systems, you will notice that after doing all of this, you still cannot connect to you VNC servcer. This is because one of two common problems or both of them. Let us make sure that these problems are solved before testing our VNC server.

First Problem:

You firewall blocks servers from listening on ports for incmming connection, so you need to enable VNC server in your firewall.

If you are using firewalld, execute the following commands:

firewall-cmd --permanent --zone=public --add-service vnc-server
firewall-cmd --reload

If you are using iptables, open the ports that are used by VNC server. To open the port, execute the following commands:

iptables -I INPUT 5 -m state --state NEW -m tcp -p tcp -m multiport --dports 5901:5990,6001:6090 -j ACCEPT
service iptables save
service iptables restart

Second Problem:

The xstartup file in ~/.vnc folder is not executable. This is a common problem on CentOS 6.x, but let us make sure that xstartup file is executable in order to get rid of any expected error. Login to the user that you set in VNC service file and execute the following command:

chmod +x ~/.vnc/xstartup

Clipboard Sharing:
In order to allow cliboard sharing between your server and VNC client, you need to keep vnc config running on your server. To run vnc config use the following command on your server:

vncconfig &

The & is used so you can close the terminal and still have vnc config running. Just minimize that dialog and you will have clipboard sharing between server and client.

Adding more users to access VNC server:
To add another user, follow the same steps you did in this tutorial, but change the port number. Here are examples.

cp /lib/systemd/system/vncserver@.service /etc/systemd/system/vncserver@:2.service

[Service]
Type=forking
User=engmah
ExecStart=/usr/bin/vncserver :2 -geometry 1280x1024 -depth 24
ExecStop=/usr/bin/vncserver -kill :2

systemctl enable vncserver@:2.service

systemctl start vncserver@:2.service

Connecting to VNC server:
Using any VNC client connect to the IP of your server and the port number of the service. The port number that you use to connect to the VNC server is the port number of the service plus 5900. For example in previous steps we used port 1 so we connect to port (5900 + 1 = 5901).

192.168.1.80:5901

Zombie Processes Explained

2014-08-01T01:33:00.003-07:00

What is zombie process?

Zombie process (of defunct as named in some systems) is a process that its execution finished and the system for some reason cannot get its return value in order to clean it from processes table. That is a zombie process is just a record in the process table in the system and not a process that is under execution.

What causes zombie process?

Take this scenario of how process can turn into a zombie:

A process forks a child process.
The child process finish its execution and waits to report its exit status to its parent process.
But the parent process is busy in processing another child process exit status, or it is poorly programmed so it do not response to children when they finish their execution (we will look at how to handle children that their execution is finished).
The system keeps the child -that its exit status is not handled by its parent- in process table in case of its parent executes wait() to get its exit status.
The zombie will stay in the process table until its exit status is handled by its parent or its parent terminates.
When the parent of a zombie is terminated normally its zombies are deleted from the process table.
If the parent is abnormally terminated its zombies are inherited by the process id 1 ( ie init ) which periodically initiate wait() and removes zombies.

Note:

When a process is abnormally terminated, all of its children are inherited by the process id 1 (ie init).
When a child is finished the kernel sends to its parent the signal SIGCHLD. Poorly programmed processes do not listen to this signal or do not handle child processes correctly. (We will look at how to handle zombies in our program later in another section).

Why Kernel Keeps Zombies?

Zombies cannot be deleted arbitrarily because their parents may be scheduling their exit status.

The programmer may plan to use the exit status of the child process later to make some decision, but not immediately after it is finished. So the system may cause a crash for that process if it get rid of zombies at its on discretion.

Only if the process terminate (normally or abnormally) the system can take care of deleting zombies.

Why Programmers Tend to Avoid Zombie Processes?

Even though that zombies almost consume nothing from the resource and share no CPU time which makes zombies have no effect on the performance on you system, programmers tend to avoid them for the following reason.

The process table of Linux systems is limited (usually 32768 processes only) so accumulating zombies can eventually (when their number is high) block the system from running new processes.

To see what is the limit of process table on your system, use this command:

    cat /proc/sys/kernel/pid_max

The zombie pid cannot be reused until it is completely deleted. So some programmers hold some zombies to make sure that they create children with unique pid ( not child is allowd to take the pid of previously terminated and child). In this situation zombies can be useful.

How to Kill Zombie Processes

You cannot just use kill or other commands to get rid of zombies. You need to kill the parent of the zombie process.

Commands to Deal with Zombie Processes

To show all zombie processes on your system use ps and then grep all lines containing Z.

    # ps -aux | grep Z

The output on Fedora 17 is

    1000 6746 0.0 0.0 0 0 pts/4 Z+ 15:59 0:00 [a.out]

Note that at the status column it used Z to indicate that it is zombie as well as ps used after the text of the command of the process to indicate that it is indeed zombie process.

Now to show the kill the parent of the zombie simply use kill with pid of the parent which can be found in the PPID (Parent Process ID) in the output of # ps -aux | grep Z

    # kill

Using KDE System Activity we see that in the "CPU %" column it used the word "zombie" to indicate zombie process

Example on program that generates zombie child processes?

In this section I will show you an example using C language on a process with zombie child process.

If the child finish its execution before the parent, the child will be marked as a zombie process.

Lets see how to build it in C languages.

    #include
    #include
    #include

    main() {
    pid_t pid;
    pid = fork();

    int n;
    n = 20;
    if(pid == 0) {
    printf("I am a child which will become a zombie process\n");
    }
    else
    sleep(n);
    return 0;
    }

We omitted the return value type on the main function because int is the default in C language.

After we fork() pid will hold 0 to indicate the child process and value other than 0 for the parent. This means

If pid == 0 this means that the current process is the child and we execute commands that we wish to be executed in the child process.

If pid != 0 this means that the current process is the parent process and we execute commands that we wish to be executed in the parent process.

You can download the C file of the code from here.

How to Handle Zombie processes in Code?

In the main function we tell the kernel that the handler of signal SIGCHLD is the function deleteChild(). This means that when the child finishes (and hence SIGCHLD signal is sent to its parent process) the kernel (which executes the process) will call the function deleteChild.

    #include
    #include
    #include
    #include

    void deleteChild(int signal_value) {
    int child_pid;
    int exit_status;
    child_pid = wait(&exit_status);
    printf("Child of PID: %d exited with status: %d\n", child_pid, exit_status);
    }

    main() {
    (void) signal(SIGCHLD, deleteChild); /* This is used to set the handle of the signal SIGCHLD is the function deleteChild */
    pid_t pid;
    pid = fork();

    int n;
    n = 20;
    if(pid == 0) {
    printf("I am a child which will become a zombie process\n");
    sleep(10);
    }
    else {
    sleep(n);
    printf("No Zombies Are Allowed\n");
    }
    return 0;
    }

You can download the C file of the code from here.

Notes About last Program:

We asked the child process to sleep for 10 seconds to let you check ps (or any GUI tool to watch processes) to insure that the PID of the child is the same as the PID that is printed by the program.

You may expected that the parent process will terminate after 20 seconds (after sleep finishes), but actually it finished after 10 seconds. This is because sleep finish under tow conditions:

The amount of time specified (eg: 20 seconds) finish.
A signal arrives at the program (in our case SIGCHLD signal).

After the signal arrives the sleep(20) will stop and the parent will continue its execution. And as demonstration we printed "No Zombies Are Allowed".

You can create a map between children pids and the exit status so you can get rid of zombies immediately and at the same time you can hold their exit status for later usage. Obviously saving the values is done inside deleteChild() function.

If you have any question, please comment.

Thanks for reading

the ordinal 459 could not be located in the dynamic link library urlmon.dll

2014-05-18T08:10:00.000-07:00

Many of us faced the following problem after updating Windows

the ordinal 459 could not be located in the dynamic link library urlmon.dll

This problem is caused by Internet Explorer 11, and the solution is to remove IE 11.

To solve the problem, follow the following steps:

From the Control Panel open Programs and Features.
From the left panel click on "Turn Windows features on of off".
A new dialog will show up.
Uncheck Internet Explorer 11; this will revert IE 11 to IE 8.
This will solve part of the whole problem, you will be able to enable themes and use
other corrupted programs, but some Windows program won't fully work, for example showing
Windows Services will still non functional, to solve all problems you need to install IE 9
of IE 10
Install IE 9 or IE 10 from Windows Updates or from Microsoft website.
Note: Do not allow Windows Updates to install IE 11 again, you can just hide this update.

If you have any question, do not forget to comment.

How to Install cpupower Package on Fedora

2013-06-19T08:14:00.003-07:00

Fedora does not define cpupower as a separate package, instead it includes it in the package kernel-tools.
So just install kernel-tools and you will get cupower.

# sudo yum install kernel-tools

How to Change User Password at Command Prompt

2013-01-30T16:22:00.000-08:00

How to use the net user command to change the user password at a Windows command prompt. Only administrators can change domain passwords at the Windows command prompt. To change a user's password at the command prompt, log on as an administrator and type: "net user * /domain" (without the quotation marks)

When you are prompted to type a password for the user, type the new password, not the existing password. After you type the new password, the system prompts you to retype the password to confirm. The password is now changed.

Alternatively, you can type the following command: net user . When you do so, the password changes without prompting you again. This command also enables you to change passwords in a batch file.

Non-administrators receive a "System error 5 has occurred. Access is denied" error message when they attempt to change the password.

Convert an int to QString in Qt

2013-01-20T14:28:00.000-08:00

Hi,
Today I will show you how to convert an int type to a QString type in Qt.

Here are the steps:

1- We start my dividing the variable on 10 using the modulo operator ( % )

int_to_convert % x

2- We convert the result to the corresponding character of the result by adding 0x30 in hexadecimal
or 48 in decimal

ch = (char)(int_to_convert % x + 0x30);

3- We insert "ch" at the beginning of the QString variable using the "insert" function and the position
is 0.

output_string->insert(0, ch); //Notice we passed the position 0.

4- We set the value of the int variable to its value divided by 10

int_to_convert = (int_to_convert / x);

5- This is the final code

void intToString(int int_to_convert, QString * output_string) {

    QChar ch;

    int x = 10;

    while(int_to_convert != 0) {

        ch = (char)(int_to_convert % x + 0x30);

        output_string->insert(0, ch);

        int_to_convert = (int_to_convert / x);

Note:
I made a header file that you can include it in your program and all you need is to pass it the
int variable and the address of your QString variable.
Download the header file from here

Simple 3 digit calculator in PIC

2012-12-15T16:27:00.000-08:00

Hi everybody
Here is a simple calculator that is designed using PIC micro-controller.
It takes tow numbers each of which is 3 digits long and performs the required operation

It has some bugs. And further updates will be posted here.

Click on the image to see the original size

Click on the image to see the original size

Here the Source code by date of modification
22/12/2012
Click here The Oldest version

Any further question or comment, please post in comments.

libstdc++.so.6: version `GLIBCXX_3.4.11' not found

2012-11-19T01:25:00.001-08:00

I encountered this problem with the LibreOffice 3.6.2.2 (Build ID: da8c1e6) on fedora 17 with Linux kernel 3.6.6-1.fc17.x86_64

I search the net and I found no clear solution so I took it on my own.

This is the error that pop up to me:

(soffice:5947): Gtk-WARNING **: /opt/libreoffice3.6/program/../ure-link/lib/libstdc++.so.6: version `GLIBCXX_3.4.15' not found (required by /usr/lib64/gtk-2.0/2.10.0/engines/liboxygen-gtk.so)

this solution applies also to this error:
(soffice:3737): Gtk-WARNING **: /opt/libreoffice3.6/program/../ure-link/lib/libstdc++.so.6: version `GLIBCXX_3.4.11' not found (required by /usr/lib64/gtk-2.0/2.10.0/engines/liboxygen-gtk.so)

or any error that related to newer versions of GLIBCXX_ like GLIBCXX_3.4.12 or GLIBCXX_3.4.13

What I found is that libstdc++.so.6 that is located in:
/opt/libreoffice3.6/program/../ure-link/lib/

does not have the "strings"
GLIBCXX_3.4.11
or of higher versions like
GLIBCXX_3.4.15

so we need a file that contains that "string" and then replace it with the old one.

And here is the solution:
1- Go to http://rpm.pbone.net
and choose Advanced Search and choose only the distribution you are using

2- Search for libstdc++ and choose the latest version that is compatible with your

architecture (x86_64, i586, i386, i686, or amd64).

What fits for me: libstdc++-4.7.0-0.12.fc17.x86_64.rpm

3- Extract the rpm package using File Roller(with gnome) or Ark (on KDE). I used Ark.

4- A new file named usr will be created, move inside it using:

# cd usr

5- Move to the directory lib or lib64 ( depending on your architecture )

# cd lib64

6- You will find two file

- libstdc++.so.6

- libstdc++.so.6.0.xx (xx depends on the version you downloaded)

and at the time of writing this post the latest version is libstdc++.so.6.0.17

7- Delete libstdc++.so.6 and rename libstdc++.so.6.0.17 to libstdc++.so.6.

8- Now rename the originale file that caused the problem and we want to replace it

(just because we need a backup for it)

# sudo mv /opt/libreoffice3.6/program/../ure-link/lib/libstdc++.so.6

/opt/libreoffice3.6/program/../ure-link/lib/libstdc++.so.6_backup

9- Now move the new file we got in step 6 and copy(or move) it to the path of the

old one that caused the problem

# sudo mv libstdc++.so.6 /opt/libreoffice3.6/program/../ure-link/lib/libstdc++.so.6

10- Run your program and your problem will be gone.

Please if you encountered any problem let me know by commenting.

If the post solved your problem, please comment.

Selection Sort Implementation In C++

2012-02-02T18:11:00.000-08:00

This is the code of the selection sort in C++

#include
using std::cout;

void swap(int * const, int * const);
void selection_sort(int [], const int);

int main()
{
    int A[] = {1, 2, 8, 74, 9, 0, -1, 7};
    selection_sort(A, 8);
    for(int i = 0; i < 8; i++)
        cout << A[i] << ' ';

}

void selection_sort(int A[], const int a_size)
{
    int index = 0;
    for(int i = 0; i < a_size; i++)
    {
        for(int j = i + 1; j < a_size; j++)
        {
            if(A[index] > A[j])
                swap(&A[index], &A[j]);
        }
        index++;
    }
}

void swap(int * const e1_ptr, int * e2_ptr)
{
    int temp = *e1_ptr;
    *e1_ptr = *e2_ptr;
    *e2_ptr = temp;
}

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Fix all VMware Issues on Linux

2012-01-08T22:03:00.000-08:00

In this post I will introduce steps to avoid all VMware installation and running issues.
These issues includes:

VMware cannot find modules.
VMware cannot find header files.
VMware cannot compile.
Installing VMware tools on Linux guest.

First: Installing the VMware bundle file
1. You need to make the bundle file executable

# sudo chmod +x the_bundle_file_name.bundle

Just replace "the_bundle_file_name.bundle" with the name of the bundle file you have

2. Now install the bundle file

# sudo ./the_bundle_file_name

Note: on openSUSE no graphical interface will appear since you will be installing using the root user. This is how things done on openSUSE, if you use su command or sudo you need the password of the root user( I think this is the best thing for desktop users ). So while installing you can install it from any user but you need to login to the root in next steps so login to the root in the graphical interface from now.

Second: Running VMware on Linux:
* Running VMware on Linux needs some packages to be installed as well as some
programs
* You can install the packages from the GUI package manager of your distribution

1. Install make

for openSUSE

# sudo zypper install make

for Fedora, CentOS, RedHat 6, Oracle Linux, or any distribution uses yum

# sudo yum install make

for Debian, Mint, Ubuntu, or any distribution uses apt-get

# sudo apt-get install make

2. Install gcc compiler

for openSUSE

# sudo zypper install gcc

for Fedora, CentOS, RedHat 6, Oracle Linux, or any distribution uses yum

# sudo yum install gcc

for Debian, Mint, Ubuntu, or any distribution uses apt-get

# sudo apt-get install gcc

3. Install kernel headers, and kernel-devel

for openSUSE

# sudo zypper install kernel-headers kernel-devel

for Fedora, CentOS, RedHat 6, Oracle Linux, or any distribution uses yum

# sudo yum install kernel-headers kernel-devel

for Debian, Mint, Ubuntu, or any distribution uses apt-get

# sudo apt-get install kernel-headers kernel-devel

* So far, we solved the issue of cannot find header file
* If the problem still there just update you system and it will be fixed
    Since the kernel-headers and kernel-devel will be of the latest kernel version of
    you distribution and by nature your installation media will have an older version
    of the kernel.
* If you have any problem please add them in the comments.

* Now we come to solve the issue of cannot find modules
* Here i strongly recommend you to login to the root in the GUI

   1. Go to this directory

/usr/lib/vmware/modules/source

In command line:

# cd /usr/lib/vmware/modules/source

2. Copy all the tar files from this directory to this one:

/tmp/vmware-root

The name of this files are:

vmblock.tar vmci.tar vmmon.tar vmnet.tar vsock.tar

In the command line:

# sudo cp * /tmp/vmware-root

3. Extract each tar file that copied to /tmp/vmware-root

In the command line:

# su then enter the root password

# cd /tmp/vmware-root

# tar -xvf vmblock.tar

# tar -xvf vmci.tar

# tar -xvf vmmon.tar

# tar -xvf vmnet.tar

# tar -xvf vsock.tar

4. Now type vmware in the command line:

# vmware

* So far we solved the issue on VMware cannot find module
* If you have any problem please add them in the comments.

* Now we come to solve Installing VMware tools on Linux guest.

Just install make, gcc, kernel-headers, and kernel-devel then start the installaton and you won't face any problem.

for openSUSE

# sudo zypper install make gcc kernel-headers kernel-devel

for Fedora, CentOS, RedHat 6, Oracle Linux, or any distribution uses yum

# sudo yum install make gcc kernel-headers kernel-devel

for Debian, Mint, Ubuntu, or any distribution uses apt-get

# sudo apt-get install make gcc kernel-headers kernel-devel

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A powerful implementation for singly linked list in java with new functions

2011-10-13T05:16:00.000-07:00

Here is an implementation for singly linked list in java
I also implemented some function -that are not in the books about data structures-
This function removes or adds elements at specific place, returns an element from a specific place and so on

Download the java files and enjoy I also created a test.java file to show you some results

Download the source file:
Click me to Download

I created it under Eclipse so for better view use it
You can download Eclipse for java from the official web site
Click Here to Download from the official website

OR you can support me by downloading them from filesonic

Eclipse for Windows 32-bit
Eclipse for Windows 64-bit

Eclipse for Mac OS X(Cocoa 32)
Eclipse for Mac OS X(Cocoa 64)

Eclipse for Linux 32-bit
Eclipse for Linux 64-bit

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Computing Fibonacci Numbers via Binary Recursion

2011-09-30T13:56:00.000-07:00

This C++ code will allow you to find the kth term in Fibonacci Series
Just compile it and you will have the results

#include
using std::cout;
using std::cin;
using std::endl;

int fibb(int);

int main()
{
    int k;
    cout << "Please enter the kth element to calculate: " << endl;
    cin >> k;
    cout << "The kth element is " << endl <}

int fibb(int kthElement)
{
    if(kthElement <= 1)               // the base case
        return kthElement;
    return fibb(kthElement - 1) + fibb(kthElement - 2); // The recursion function
}

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VMware cannot find kernel headers eaven they are installed

2011-09-30T11:22:00.000-07:00

I made a new post that contains the solution to all VMware installation problems on Linux
You can visit it HERE

This problem is caused when the kernel headers are installed but the kernel-devel is not and to solve this problem just install them using this command:

sudo yum install kernel-devel

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Fix chmsee error on Linux

2011-09-28T23:49:00.000-07:00

When i updated my Linux ( fedora 15 lovelook ) chmsee stopped working and i tried other chm viewers but they do not show special characters and the chm file looks like a mass.

After googling for this problem for a while a figured that no one got a solution for this so i decided to take it on my own and i finally ( Sure thanks to Allah ) fixed it.

What is going wrong?
The problem that fully update updates every package that has an update and unfurtionatily it updates mozilla firefox

Mozilla firefox 6.0 uses xulrunner and so chmsee does but chmsee uses xulrunner-2.0.1-1.fc15.x86_64.rpm ( and firefox 4.0 uses it ) but firefox 6.0 uses xulrunner.x86_64 0:6.0.2-1.fc15 that is not compatible with chmsee and it will crash

The good news that I got the solution which is you need to setup xulrunner-2.0.1-1.fc15.x86_64.rpm and also firefox 4.0 since 6.0 won't work

To do that use this command:

sudo yum downgrade xulrunner

What does this mean?
1- sudo & yum

Everyone know about it

2- downgrade

This will uninstall the current version on the package and install the previous version of that package which in our case what will solve the problem.

3- xulrunner

Tha name of the package that we want to downgrade.

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YUM over proxy

2011-09-28T21:46:00.000-07:00

You need to update yum.conf and add proxy configurations

1- sudo vi /etc/yum.conf

2- Add the following:

            # The proxy server - server: port
            proxy=http://proxyName:Port_Number
            # If proxy authentication is required
            proxy_username=proxy_user
            proxy_password=proxy_user_password

3- In some cases you need to define this variable:
            http_proxy='http://proxy_Name:port_Number'

4- If your proxy is perminant you can export that variable to make it perminant:
    sudo export http_proxy='http://proxy_Name:port_Number'

Now if you want to use direct connection as in my case at home i use direct connection and at university i use proxy just put # in the front of the lines you have inserted to the configuration file this will make them comments and yum will ignore comments and when you want to use proxy just delete the # except this lines
            # The proxy server - server: port
            # If proxy authentication is required
Because they must be comments and used to let you know easily where the proxy configuration are

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VMware 8 cannot find kernel-headers

2011-09-22T21:02:00.000-07:00

I recently installed VMware 8 but it cannot find the kernel-headers and the fixes and patch on the Internet are for VMware 7.14 so i opened the command line and read the error and I realise that some files are not on its place so VMware cannot find them

I made a new post that contains the solution to all VMware installation problems on Linux
You can visit it HERE

The files are the modules for VMware and every one knows where they are
but before that we have to do somethings

1- Install make, kernel-headers, gcc compiler, and kernel-devel

# sudo yum install gcc.x86_64

# sudo yum install make

# sudo yum install kernel-headers

# sudo yum install kernel-devel

2- Now we need to update the system

# sudo yum update

By now we finished the first step now we need to put the modules in it files

VMware looks for the modules in

/tmp/vmware-USER_NAME

USER_NAME: is the name of the user you will run vmware products from it

lets assume in is eng-mah

but the actual place for this modules is

/usr/lib/vmware/modules/source

and they are tar file not folders so we have to copy the tar files from its original place (/usr/lib/vmware/modules/source) to (/tmp/vmware-USER_NAME) and the decompress each tar file separately so you will have the follwoing folders:
    vmblock-only
    vmci-only
    vmmon-only
    vmnet-only
    vsock-only

Now you just open the command line and type:

# sudo vmware

Its will take 2 or more minutes and you will see the progress and the VMware will run
Gongratulations

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VMware cannot compile modules in kernel 2.6.40*

2011-08-22T03:28:00.000-07:00

If you update you Linux and VMware just went down and saying that
it needs to compile somethings and load some modules to your kernel and
then every thing goes wrong

I tried a lot of patches on the net and nothing works for kernel 2.6.40 and later

and after investing a lot of time in this problem here is the solution

I made a new post that contains the solution to all VMware installation problems on Linux
You can visit it HERE

This is an update for this topic
before doing the steps you need to download a patch and apply it then
you can do the steps if the patch did not bear fruit

to download the patch Click Here

The maker of the patch is from

Weltall's blog

The link of the original patch post

Patch post

I executed the patch but only executing it is not enough and i found that the files are not in its place so now we are going to put the in place
Note: if you use VMware 8 this steps do not work this topic goes for VMware 8

Now if the path did not work it does not mean that it did not do its job

Th problem is that the fixed modules are not in its place so by following this steps you will but the modules in its right place

First of all log into your system as root using

su

1- Go to

/usr/lib/vmware/modules

2- Copy its content to any place, in my case i copied it to

~/Desktop/New Folder

3- Extract the tar file you copied each one to its own folder and make sure that you have the following folders contains some folders and file that VMware will use

    vmblock-only
    vmci-only
    vmmon-only
    vmnet-only
    vsock-only

4- In command line go to:

/tmp/vmware-root

5- Copy the tar files and the extracted folders directly to this folder.
6- Run the a VMware product ( Workstation or Player) and it will compile and load the necessary modules to your kernel

** Note that i have uploaded the modules that is working for my Linux (Fedora 15 with kernel 2.6.40.3-0.fc15.x86_64 Using Xfce desktop environment)

Download the module from here

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View, Browse, and Extract ISO files in linux

2011-07-31T13:04:00.000-07:00

To browse ISO files in Linux you have to mount them and then you can browse or copy the files and folders that are inside ISO file

To do so follow the following instructions:
1- Open terminal
2- Write the following command

sudo mount -o loop iso_File_Location mount_Location

3- iso_File_Location is the location of the iso file and make sure that you typed
iso name e.g.:

/home/temp_User/Desktop/temp.iso

4- mount_Location is the name of the folder where you want to mount the iso
file e.g.:

/home/temp_User/Desktop/temp

5- To unmount the ISO file

sudo umount mount_Location

Note you can install gcombust.x86_64 which is a GUI program and is equivalent to the applications that mounts ISO files in Windows