C99 Server

This is an example/base/template application showing how its possible to code a portable application using containers.

My Stack

• IDE: VSCode (code) on Windows 11 w/ clangd language server
• Compiler: clang (build happens inside Container)
• Compile Target: Podman Desktop > Podman Machine (WSL2) > Podman Container, running Alpine Linux
• Debugger: lldb client, connected to remote lldb-server (in Container)

My Code Style

Learn my particular approach to coding portable code in C99.

• see: docs/my-code-style.md

Install / Prerequisites

• Install LLVM v20.1.8 from llvm/llvm-project releases
  • (bug workaround) Install specifically Python 3.10.10 Windows embeddable package (64-bit) by extracting it to C:\Program Files (x86)\LLVM\bin.
• VSCode Extensions
  • Required
    • ms-vscode.cpptools
    • llvm-vs-code-extensions.vscode-clangd
    • llvm-vs-code-extensions.lldb-dap
  • Recommended
    • GitHub.copilot
    • GitHub.copilot-chat
    • bierner.markdown-mermaid
    • spmeesseman.vscode-taskexplorer
    • ms-vscode-remote.remote-wsl

Build & Run (w/ Debug)

Use the VSCode launch.json launch configuration:

• Debug main: main program
• Debug test: currently open unit test (ie. test/**/*.c)

LLDB Troubleshooting Tips

The main trick here is we are cross-compiling from (any OS) to Linux using Clang.
Likewise, we are cross-debugging to Linux using LLDB.

• LLDB client and server versions should match

• You can automate the CLI by sending a chain of commands:

  lldb -o "platform select remote-linux" -o "platform connect connect://localhost:2345" 

• Connecting the client manually:

  # (probably unnecessary) disable ASLR in WSL2 podman machine
  settings set target.disable-aslr false
  
  target create build/main
  settings set target.source-map /app z:\tmp
  breakpoint set -f src/main.c -l 14
  breakpoint clear -f src/main.c -l 14
  process launch
  

• If you suspect the compiler is not emitting debug symbols correctly:

  readelf -S build/main
  readelf --debug-dump=info build/main | grep DW_AT_name
  nm -a build/main