Adapter (Wrapper) Pattern

Convert interface of one module to interface expected by another. Enables integration of incompatible interfaces without modifying either.

ikigai Application

wrapper.h: Adapts system calls to mockable interface:

• posix_read_() wraps read()
• curl_easy_perform_() wraps libcurl
• yyjson_read_file_() wraps yyjson

Purpose: Real implementations in production, mock implementations in tests via weak symbol linking.

LLM providers: Adapt different API formats (OpenAI, Anthropic) to unified internal message format.

Benefit: External dependencies isolated behind stable internal interface. Swap implementations without changing callers.

Testing: Inject failures, control responses, verify calls.