Linux Programming Discussion Boards

markkuk7-Jul-20 21:32

7-Jul-20 21:32

FTP would require both installation and configuration on the Linux machines. SSH service is installed by default but not enabled.

Re: Reading Files on network box

kalberts7-Jul-20 22:02

kalberts

7-Jul-20 22:02

Is not FTP installed by default on all Linux machines nowadays?

I honestly would have taken that for granted. FTP was developed in the days when you measured program size in kilobytes. The protocol is so simple that a student could implement it as homework assignment #3. I can't see any reason for taking it out.

Re: Reading Files on network box

markkuk7-Jul-20 22:23

markkuk

7-Jul-20 22:23

Member 7989122 wrote:
Is not FTP installed by default on all Linux machines nowadays?

No, not anymore. There are better replacements such as SFTP or SCP. Curl or wget can be used as FTP clients if absolutely necessary.

Member 7989122 wrote:
FTP was developed in the days when you measured program size in kilobytes.

Those days nobody could imagine the need for network security. FTP transmits everything, including user credentials, in cleartext. The protocol design makes it difficult to pass through firewalls without causing additional security risks. In general, it's just too dangerous and should not be used.

Re: Reading Files on network box

Gerry Schmitz8-Jul-20 6:03

Gerry Schmitz

8-Jul-20 6:03

Quote:
If you are connecting to an FTP server that requires credentials and supports Secure Sockets Layer (SSL), you should set EnableSsl to true.

And there's one's own encryption / decryption, staging directories, etc. Keep the baby.

It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it.
― Confucian Analects: Rules of Confucius about his food

Re: Reading Files on network box

Josh Gray210-Jul-20 4:37

Josh Gray2

10-Jul-20 4:37

Do you want to force linux to do the windows thing, or windows to do the linux thing?

For the former run samba on the linux box and create shares you can access from windows. This will probably suck, the degree to which it sucks will depend on the file system you are using on the linux side.

For the latter you can run an ftp server on the linux side or setup ssh and use scp. These will suck less.

Re: Reading Files on network box

#realJSOP10-Jul-20 5:07

#realJSOP

10-Jul-20 5:07

I found a solution - use the SshNet library and I don't have to do anything on the other pi's on the network.

".45 ACP - because shooting twice is just silly" - JSOP, 2010
-----
You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010
-----
When you pry the gun from my cold dead hands, be careful - the barrel will be very hot. - JSOP, 2013

Re: Reading Files on network box

Member 1330167920-Dec-20 23:33

Member 13301679

20-Dec-20 23:33

Quote:
Facts:

0) I'm writing a .Net Core 3.1 command line app (using C#) to read text files on some [...] machines on the network.[...]

[...]

2) I don't want to create shares of these folders.

If those files aren't shared, how do you expect to read them? after all, if those remote files were on Windows, you'd still need to share them for a remote computer to read them.

You appear to be under the impression that, on Linux, all files are shared by default. I can assure you that this is not the case.

[...]
How do I go about reading a file on a remote linux box?

Same way you would on a Windows box: you'd create a share.

A second option is to install some sort of file server on the Pis(ftp, http, ssh/scp, etc) and use that to copy the files across.

Re: Reading Files on network box

#realJSOP21-Dec-20 0:35

#realJSOP

21-Dec-20 0:35

You really should read the whole thread. The solution has been found.

Glade C++ Maximizing the window

Member 1485117218-Jun-20 5:49

Member 14851172

18-Jun-20 5:49

so i have Ubuntu 20.04 and i am using Glade v3.36 so my issue is i want to be able to have my Glade form Maximize when the Form Shows on the screen, can anyone help me get the Form to maximize programmatically . thank you

C++

#include <gtk/gtk.h>

typedef struct {
    GtkWidget *w_dlg_file_choose;       // Pointer to file chooser dialog box
    GtkWidget *w_img_main;              // Pointer to image widget
    GtkWidget      *image;
} app_widgets;

gchar *file_name = "image1.jpg";        // Name of file to open from dialog box
// image = gtk_image_new_from_file ("splash1.jpg");

int main(int argc, char *argv[]) {
    GtkBuilder      *builder;
    GtkWidget       *window;

    app_widgets     *widgets = g_slice_new(app_widgets);
    // gchar *file_name = "file.jpg";        // Name of file to open 
    gtk_init(&argc, &argv);

    // image = gtk_image_new_from_file ("splash1.jpg");
    builder = gtk_builder_new_from_file("glade/window_main.glade");
    window = GTK_WIDGET(gtk_builder_get_object(builder, "window_main"));
    widgets->w_dlg_file_choose = GTK_WIDGET(gtk_builder_get_object(builder, "dlg_file_choose"));
    widgets->w_img_main = GTK_WIDGET(gtk_builder_get_object(builder, "img_main"));
    gtk_builder_connect_signals(builder, widgets);
    //image = gtk_image_new_from_file ("myfile.png");
    // gtk_image_set_from_file(GTK_IMAGE(app_wdgts->w_img_main), file_name);
    g_object_unref(builder);
    gtk_widget_show(window);                
    gtk_main();
    g_slice_free(app_widgets, widgets);
    return 0;
}

glade display an image

Member 148511722-Jun-20 5:15

Member 14851172

2-Jun-20 5:15

I know I am missing something really simple here, but all I am trying to do is display a image from a jpg file on a glade form statically w/o a file chooser, here is my code so far, any help would be great.

C++

<pre>#include <gtk/gtk.h>

typedef struct {
    GtkWidget *w_dlg_file_choose;       // Pointer to file chooser dialog box
    GtkWidget *w_img_main;              // Pointer to image widget
    GtkWidget      *image;
} app_widgets;

gchar *file_name = "image1.jpg";        // Name of file to open from dialog box
// image = gtk_image_new_from_file ("splash1.jpg");

int main(int argc, char *argv[]) {
    GtkBuilder      *builder;
    GtkWidget       *window;

    app_widgets     *widgets = g_slice_new(app_widgets);
    // gchar *file_name = "file.jpg";        // Name of file to open 
    gtk_init(&argc, &argv);

    // image = gtk_image_new_from_file ("splash1.jpg");
    builder = gtk_builder_new_from_file("glade/window_main.glade");
    window = GTK_WIDGET(gtk_builder_get_object(builder, "window_main"));
    widgets->w_dlg_file_choose = GTK_WIDGET(gtk_builder_get_object(builder, "dlg_file_choose"));
    widgets->w_img_main = GTK_WIDGET(gtk_builder_get_object(builder, "img_main"));
    gtk_builder_connect_signals(builder, widgets);
    //image = gtk_image_new_from_file ("myfile.png");
    // gtk_image_set_from_file(GTK_IMAGE(app_wdgts->w_img_main), file_name);
    g_object_unref(builder);
    gtk_widget_show(window);                
    gtk_main();
    g_slice_free(app_widgets, widgets);
    return 0;
}
//////////- GUI Button-Signals-"no dragons here" - ///////////////////////////
/////////////////////////////////////////////////////////////////
// Event hanlders. Must be extern "C"

// File --> Open
void on_info_btn_clicked() {
    gtk_main_quit();
}

// called when window is closed
void on_window_main_destroy() {
    gtk_main_quit();
}

Re: glade display an image

Richard MacCutchan2-Jun-20 5:26

Richard MacCutchan

2-Jun-20 5:26

Member 14851172 wrote:
I know I am missing something really simple here

Yes, the details of your problem.

More advise wanted - how to run TWO loops ?

Vaclav_13-Mar-20 15:23

Vaclav_

13-Mar-20 15:23

Here is the latest snag I am against.
Main part of my application is to WAIT to receive data.
In fancy techno talk - I have a server in "accept" state - waiting to receive data - hence processing is stopped.

The data received is processed and then passed to OpenGL - OpenGL is in similar waiting state "they" call glutMainLoop();

Obviously unworkable situation - cannot have two waiting state. .

Found "fork" which creates two processes , but they do not share variables.
Looking at socketpair to solve that "problem".

Now it looks as proverbial "long way around the barn"...

Any other "professional" suggestion ?

Not really sure how to debug such setup - jumping between processes , but willing to try it.

Re: More advise wanted - how to run TWO loops ?

Peter_in_278013-Mar-20 18:31

Peter_in_2780

13-Mar-20 18:31

One word to read up on...

threads

Cheers,
Peter

Software rusts. Simon Stephenson, ca 1994. So does this signature. me, 2012

Re: More advise wanted - how to run TWO loops ?

Richard MacCutchan13-Mar-20 23:09

Richard MacCutchan

13-Mar-20 23:09

Multiple processes can happily share variables in global memory. They just need to use semaphores or mutexes to synchronise their access. Just about every application running on the web, on desktops, phones etc. uses these features.

Re: More advise wanted - how to run TWO loops ?

Member 1477303714-Mar-20 20:42

Member 14773037

14-Mar-20 20:42

fork() and signal() - that's what I used in the 1980's and 1990's before POSIX 4 (later POSIX 1a now pthreads and more recently, threads native to C11 and C++11) came into being. This includes sigwait(), sigpause(), sigsuspend(), etc. Some of these work with threads. It might be possible to emulate the functionality of all concurrency primitives with these elements alone.

You can look under the POSIX Standard for more information The Open Group Base Specifications Issue 7, 2018 edition[^]

There is already a multi-platform Pause-Resume thread framework on this site. That's what landed me on this web site. It's right here Data Processing Thread with the Pause/Resume Functionality[^]

Re: More advise wanted - how to run TWO loops ?

CPallini2-Apr-20 20:47

CPallini

2-Apr-20 20:47

I would second Peter_in_2780 suggestion. With modern C++ (assuming you are using C++) it is as friendly as shown in the sample code of this page: std::thread::thread - cppreference.com[^].

SOLVED Re: More advise wanted - how to run TWO loops ?

Vaclav_3-Apr-20 5:13

Vaclav_

3-Apr-20 5:13

I generally use KISS approach.
The task is to have two event "loops" , one monitoring the bluetooth input and the other processing and displaying results.
"fork" does the job.
Besides - as I continue to build the app it is not pure C++, such as OpenGL is "just" C.

Re: SOLVED Re: More advise wanted - how to run TWO loops ?

CPallini3-Apr-20 5:42

CPallini

3-Apr-20 5:42

KISS can be subjective.
In my opinion, fork is not more KISS than threads, because you have to go through IPC.

Re: More advise wanted - how to run TWO loops ?

Member 1330167920-Dec-20 23:35

Member 13301679

20-Dec-20 23:35

Follow the directions here:

man pthread_create

Seeking professional advise...

Vaclav_9-Mar-20 19:14

Vaclav_

9-Mar-20 19:14

OK, I will open myself for ridicule...
I WIIL (eventually) display real calculated data on Smith chart.

Smith chart - Wikipedia[^]

I can handle the math, what I see as a small issue is the actual GUI implementation.
I have few MAJOR choices - OpenGL, GTK and Cairo.
I found very promising code written for GTK and apparently using Cairo too.
(Cairo being 2D graph tool is my initial take on it).
I am not so sure about basic "window / form /view " - I see OpenGL as the simplest.
( I wish the "industry" woudl come up with uniform desorption / definition of the thing which was called when I started "coding" "window" - no capital W !

The advise I am seeking is

Are there other , simple, 2D graphic tools ?

I do not need spinning cube , shading, license plate recognition etc,

Cheers

Re: Seeking professional advise...

k505410-Mar-20 4:29

k5054

10-Mar-20 4:29

Google might be your friend here. A quick google for "linux smith chart" pulled up this: Ubuntu Manpage: gsmc - A GTK Smith Chart Calculator for RF impedance matching Even if gsmc isn't what you're looking for, looking at the source could help you on your way.

Re: Seeking professional advise...

Vaclav_10-Mar-20 5:12

Vaclav_

10-Mar-20 5:12

Thanks, nice reference.
I have already found another GTK application, so the "math" is covered.

PS
Me asking Mrs Google "linux smith chart" returned no useful info!
Must be my accent.

Re: Seeking professional advise...

Richard MacCutchan10-Mar-20 5:48

Richard MacCutchan

10-Mar-20 5:48

Goodness knows what you typed into Google: linux smith chart - Google Search[^]

Re: Seeking professional advise...

Joe Woodbury9-Jul-20 7:41

Joe Woodbury

9-Jul-20 7:41

You could try SFML[^] or Qt[^]

Using bluetooth connection asynchronously - C++

Vaclav_7-Mar-20 8:49

Vaclav_

7-Mar-20 8:49

Edit
Since the server is in listen /accept waiting mode all I should worry about timeout.
I can set the socket to take care of that.
I just test client to send multiple single message - in 5 second interval and reinitialized the client socket each time. Works fine for my task.

It has been a challenge , but I finally have bluetooth connection passing simple text message from client to server.
My task is to be able to utilize such connection as necessary, hence not keeping it in any kinda-of synchronous loop.
At present the communication will always be from client to server , and started by client. .

Basically I am looking for a way to check "is server connected ? ".

I do not see any issues closing the client socket and reinitializing it when new communication is required.

I hope I can instruct server socket (timeout ?) to stay connected in "accept" function...

However, I have been reading up on "select"

<a href="http://man7.org/linux/man-pages/man2/select_tut.2.html">select_tut(2) - Linux manual page</a>[<a href="http://man7.org/linux/man-pages/man2/select_tut.2.html" target="_blank" title="New Window">^</a>]

and wondering if that woudl be "cleaner" way to run this asynchronously by monitoring the state of the connection when necessary.

Maybe I'll be over my head again using select...

Any commentaries (to the subject) or other suggestion will be appreciated.

modified 7-Mar-20 16:40pm.

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