Zvals

In this chapter the zval data structure, which is used to represent arbitrary PHP values, is introduced. We explain the concepts behind zvals and how to use them in extension code.

Contents:

• Basic structure
  • Types and values
  • The zval struct
  • Access macros
• Memory management
  • Reference-counted values
  • Zval memory management
• References
  • Reference semantics
  • Representation
  • Initializing references
  • Dereferencing and unwrapping
  • Indirect zvals
• Casts and operations
  • Casts
  • Operations