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Introduction to the Rust language

Preliminaries

Basics

Fundamentals

Proficiency

Expertise

31 Memory (v) - Smart pointers

32 Polymorphism (v) - Traits

33 Error handling (ii) - Panic & Result

34 Error handling (iii) - Propagation

35 Error handling (iv) - Error trait

36 I/O (ii) - File system

37 Memory (vi) - Ref counters and cycles

39 Memory (vii) - Clone-on-write pointer

40 I/O (iii) - Command line & logs

40.1 Command line arguments 40.2 Log messages

41 I/O (iv) - Formatters

Mastery

Appendices

Command line arguments

I/O (iv) - Formatters

40.2 Log messages

October 1, 2026

Draft

This section is still being written.

40.2.1Built-in debug messages¶

Print a debug message:

dbg!("My msg");

[src/lib.rs:6:1] "My msg" = "My msg"

let a = 12;
dbg!(a);

[src/lib.rs:96:1] a = 12

Command line arguments

I/O (iv) - Formatters