Download BitBake User Manual

Table of Contents
1. Overview ............................................................................................................................... 1
1.1. Introduction ................................................................................................................ 1
1.2. History and Goals ....................................................................................................... 1
1.3. Concepts .................................................................................................................... 2
1.3.1. Recipes ............................................................................................................ 2
1.3.2. Configuration Files ........................................................................................... 2
1.3.3. Classes ............................................................................................................ 3
1.3.4. Layers ............................................................................................................. 3
1.3.5. Append Files .................................................................................................... 3
1.4. Obtaining BitBake ....................................................................................................... 3
1.5. The BitBake Command ............................................................................................... 4
1.5.1. Usage and syntax ............................................................................................ 4
1.5.2. Examples ......................................................................................................... 5
2. Execution .............................................................................................................................. 8
2.1. Parsing the Base Configuration Metadata .................................................................... 8
2.2. Locating and Parsing Recipes ...................................................................................... 9
2.3. Preferences and Providers ......................................................................................... 10
2.4. Dependencies ........................................................................................................... 11
2.5. The Task List ............................................................................................................ 11
2.6. Executing Tasks ........................................................................................................ 12
2.7. Checksums (Signatures) ............................................................................................ 12
2.8. Setscene ................................................................................................................... 14
3. Syntax and Operators .......................................................................................................... 16
3.1. Basic Syntax ............................................................................................................. 16
3.1.1. Basic Variable Setting .................................................................................... 16
3.1.2. Variable Expansion ......................................................................................... 16
3.1.3. Setting a default value (?=) ........................................................................... 16
3.1.4. Setting a weak default value (??=) ................................................................. 17
3.1.5. Immediate variable expansion (:=) ................................................................. 17
3.1.6. Appending (+=) and prepending (=+) With Spaces ......................................... 17
3.1.7. Appending (.=) and Prepending (=.) Without Spaces ....................................... 17
3.1.8. Appending and Prepending (Override Style Syntax) ......................................... 18
3.1.9. Removal (Override Style Syntax) .................................................................... 18
3.1.10. Variable Flag Syntax ..................................................................................... 18
3.1.11. Inline Python Variable Expansion .................................................................. 19
3.1.12. Providing Pathnames .................................................................................... 19
3.2. Conditional Syntax (Overrides) .................................................................................. 19
3.2.1. Conditional Metadata ..................................................................................... 19
3.2.2. Key Expansion ............................................................................................... 20
3.2.3. Examples ....................................................................................................... 20
3.3. Sharing Functionality ................................................................................................. 21
3.3.1. Locating Include and Class Files ..................................................................... 21
3.3.2. inherit Directive .......................................................................................... 21
3.3.3. include Directive .......................................................................................... 21
3.3.4. require Directive .......................................................................................... 22
3.3.5. INHERIT Configuration Directive ..................................................................... 22
3.4. Functions .................................................................................................................. 22
3.4.1. Shell Functions ............................................................................................... 23
3.4.2. BitBake Style Python Functions ....................................................................... 23
3.4.3. Python Functions ............................................................................................ 23
3.4.4. Anonymous Python Functions ......................................................................... 24
3.4.5. Flexible Inheritance for Class Functions ........................................................... 24
3.5. Tasks ........................................................................................................................ 25
3.5.1. Promoting a Function to a Task ....................................................................... 25
3.5.2. Deleting a Task .............................................................................................. 25
3.5.3. Passing Information Into the Build Task Environment ....................................... 26
3.6. Variable Flags ........................................................................................................... 26
3.7. Events ...................................................................................................................... 27
3.8. Variants - Class Extension Mechanism ....................................................................... 28
3.9. Dependencies ........................................................................................................... 29
3.9.1. Dependencies Internal to the .bb File ............................................................. 29
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