Debug Log Skill | Agent Skills

Debug Log

Printf-style logging for development and debugging. Compiles away completely in release builds.

Purpose

Development-time visibility into program state
Add arbitrary trace points during debugging
Zero overhead in release builds

Usage

#include "debug_log.h"

DEBUG_LOG("value=%d state=%s", x, state_name);
DEBUG_LOG("=== Entering function ===");
DEBUG_LOG("buffer contents: %.*s", (int)len, buf);

Build Configuration

| Build | DEBUG defined | Behavior | |-------|---------------|----------| | Debug | Yes | Writes to $IKIGAI_LOG_DIR/debug.log | | Release | No | Compiles to ((void)0) - removed entirely |

Initialization

In debug builds, call once early in main():

#ifdef DEBUG
ik_debug_log_init();
#endif

Or simply use the macro form (safe in any build):

ik_debug_log_init();  // No-op if DEBUG not defined

Output Format

[2025-01-15 10:30:00] src/client.c:34:main: === Session starting, PID=12345 ===

Format: [timestamp] file:line:function: message

Log Location

Current session: $IKIGAI_LOG_DIR/debug.log (default: .ikigai/logs/debug.log)
Previous sessions: archived as $IKIGAI_LOG_DIR/YYYY-MM-DDTHH-MM-SS±HH-MM.log using the file's birth time
Archive is skipped if the target already exists (session lasted < 1 s)
debug.log is truncated on each new run

IKIGAI_LOG_DIR must be set or the process panics at startup. It is exported by .envrc.

Inspecting Logs

tail -f .ikigai/logs/debug.log            # follow current session
ls .ikigai/logs/                           # list all archived sessions

Alternate Buffer Note

ikigai runs in terminal alternate buffer mode. printf() and fprintf(stderr, ...) are not visible during execution. Use DEBUG_LOG instead.

Source Files

apps/ikigai/debug_log.h - Macro definition
apps/ikigai/debug_log.c - Implementation (excluded from coverage)

Agent Skills: Debug Log

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