Introduction to dlv

Delve, often referred to as dlv, is a powerful debugger tailored specifically for the Go programming language. It is widely used by developers to debug Go programs efficiently. This ultimate guide will introduce you to the various API functionalities provided by dlv and demonstrate their usage with practical examples.

Basic Usage

To get started with dlv, you need to install it first:

  
  go install github.com/go-delve/delve/cmd/dlv@latest
  

Once installed, you can start debugging your application with the following command:

  
  dlv debug main.go
  

Commonly Used APIs

Launching and Attaching to a Program

Launch a program:

  
  dlv debug
  dlv exec ./myapp
  

Attach to a running process:

  
  dlv attach 
  

Breakpoints Management

Set a breakpoint at a specific function or line:

  
  b main.main
  b main.go:10
  

List all breakpoints:

  
  break list
  

Remove a breakpoint:

  
  clear 
  

Control Execution

Continue program execution:

  
  continue
  

Step through the code:

  
  step
  step-instruction
  next
  

Inspect Program State

Print the value of a variable:

  
  print 
  

Evaluate an expression:

  
  expr 
  

List stack frames:

  
  stack
  

Configuration and Scripting

Load a configuration file:

  
  dlv --config dlv.toml
  

Run commands from a script file:

  
  dlv debug --init script.dlv
  

Example Application

Consider a simple Go application for illustration:

  
  package main

  import "fmt"

  func main() {
      fmt.Println("Hello, Delve!")
      result := add(3, 4)
      fmt.Println("Result:", result)
  }

  func add(a, b int) int {
      return a + b
  }
  

To debug this application with dlv:

  
  dlv debug main.go
  (dlv) b main.add
  (dlv) c
  

This way, you can step through the add function and inspect its behavior.

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