gen_snapshot_linux_x64: cannot execute binary file: Exec format error

[jlia0]

I use the gen_snapshot_linux_x64 executable that you provide in the engine-binaries branch. However it does not work and it shows that it cannot execute binary file.

I used chmod 777 gen_snapshot_linux_x64 too.

[jlia0]

For the step of: Building the app.so (for running your app in Release/Profile mode), is a little bit confusing. Do you mind giving a walkthrough?

And also, I built the kernel snapshot on Mac OS, do I expect to build app.so on Mac too or Linux on my RPi?

Thank you!

[ardera]

I use the gen_snapshot_linux_x64 executable that you provide in the engine-binaries branch. However it does not work and it shows that it cannot execute binary file.

And also, I built the kernel snapshot on Mac OS, do I expect to build app.so on Mac too or Linux on my RPi?

The gen_snapshot_linux_x64 executable sadly needs to be executed on linux running on a x64 machine. This is because that gen_snapshot executable is actually only a side-product of compiling the engine. If I wanted to build a gen_snapshot that can be run on MacOS or Windows, I'd have to maintain multiple cross-compiling toolchains. You can try running the gen_snapshot_linux_x64 in a virtual machine though

Regarding the outputted app.so, the machine you invoke gen_snapshot on is irrelevant. It always builds an app.so that can be used on the Raspberry Pi. (More precisely, an app.so that is compiled for ARMv7 and uses hardfp ABI). The app.so target architecture, ABI, etc was specified when compiling the gen_snapshot executable.

Btw, that app.so is the only file containing platform-specific code. The kernel_snapshot.dill, kernel_blob.bin file etc only contain dart bytecode.

For the step of: Building the app.so (for running your app in Release/Profile mode), is a little bit confusing. Do you mind giving a walkthrough?

The text I wrote in the readme was meant as a walktrough 😅 If you tell me what you find confusing I can try to clarify it

[jlia0]

I use the gen_snapshot_linux_x64 executable that you provide in the engine-binaries branch. However it does not work and it shows that it cannot execute binary file.

And also, I built the kernel snapshot on Mac OS, do I expect to build app.so on Mac too or Linux on my RPi?

The gen_snapshot_linux_x64 executable sadly needs to be executed on linux running on a x64 machine. This is because that gen_snapshot executable is actually only a side-product of compiling the engine. If I wanted to build a gen_snapshot that can be run on MacOS or Windows, I'd have to maintain multiple cross-compiling toolchains. You can try running the gen_snapshot_linux_x64 in a virtual machine though

Regarding the outputted app.so, the machine you invoke gen_snapshot on is irrelevant. It always builds an app.so that can be used on the Raspberry Pi. (More precisely, an app.so that is compiled for ARMv7 and uses hardfp ABI). The app.so target architecture, ABI, etc was specified when compiling the gen_snapshot executable.

Btw, that app.so is the only file containing platform-specific code. The kernel_snapshot.dill, kernel_blob.bin file etc only contain dart bytecode.

For the step of: Building the app.so (for running your app in Release/Profile mode), is a little bit confusing. Do you mind giving a walkthrough?

The text I wrote in the readme was meant as a walkthrough 😅 If you tell me what you find confusing I can try to clarify it

Thanks. I think I got it. I can try to compile gen_snapshot on Mac OS.

And I have another question. I run the Flutter app on flutter-pi from SSH, and I saw that there is a debugger running: flutter: Observatory listening on http://127.0.0.1:41511/tcgmfJ-m1bA=/. However, I can't access this page and I think that would be a really good feature for debugging since debugging on flutter-pi is difficult.

And also, how can I quit the current flutter app and go back to the console? My current way is ctrl+c in the SSH connection to close. But if I don't have a ssh connection, how can I close the Flutter app?

[ardera]

And I have another question. I run the Flutter app on flutter-pi from SSH, and I saw that there is a debugger running: flutter: Observatory listening on http://127.0.0.1:41511/tcgmfJ-m1bA=/. However, I can't access this page and I think that would be a really good feature for debugging since debugging on flutter-pi is difficult.

Exactly, that's the dart observatory. If you would enter this URL on a browser on the Pi, you would see it. "127.0.0.1" always means localhost, so if you enter that url on your Mac, it tries accessing :41511 on your mac, and that fails of course.

There are 2 engine options that help us out here: --observatory-host <ip addr> and --observatory-port <port>
In your case, just find out the local IP address of your pi (maybe using ifconfig). You can use any port you want, like 8080.

The engine options are specified after the asset bundle path in the flutter-pi invocation, so with 192.168.178.11 as the IP address and 8080 as the port it'd look like this:
flutter-pi ~/devel/my_flutter_assets --observatory-host 192.168.178.11 --observatory-port 8080

[jlia0]

And I have another question. I run the Flutter app on flutter-pi from SSH, and I saw that there is a debugger running: flutter: Observatory listening on http://127.0.0.1:41511/tcgmfJ-m1bA=/. However, I can't access this page and I think that would be a really good feature for debugging since debugging on flutter-pi is difficult.

Exactly, that's the dart observatory. If you would enter this URL on a browser on the Pi, you would see it. "127.0.0.1" always means localhost, so if you enter that url on your Mac, it tries accessing :41511 on your mac, and that fails of course.

There are 2 engine options that help us out here: --observatory-host <ip addr> and --observatory-port <port>
In your case, just find out the local IP address of your pi (maybe using ifconfig). You can use any port you want, like 8080.

The engine options are specified after the asset bundle path in the flutter-pi invocation, so with 192.168.178.11 as the IP address and 8080 as the port it'd look like this:
flutter-pi ~/devel/my_flutter_assets --observatory-host 192.168.178.11 --observatory-port 8080

I tried putting --observatory-host <ip addr> and --observatory-port <port> when I ran the app on flutter-pi. But still I cannot access the dart observatory. I tried all these IP addresses like: http://<Pi_IP_addr>:<Pi_Port>/2Cark3_13Yo=/, http://<Pi_IP_addr>:<Pi_Port>. What's the correct way to access to the dart observatory?

[ardera]

Sorry, the engine options need to be --observatory-host=<ip addr> and --observatory-port=<port>. That was my bad, I always forget about the equals sign.

I'll also add some instructions for this to the readme.