<!--
title: Explicit value specifications
domain: ml-systems
topic: Null Handling
language: Other
source: commaai/openpilot
updated: 2025-07-23
url: https://awesomereviewers.com/reviewers/openpilot-explicit-value-specifications/
-->

Always use explicit value specifications and type-safe handling to prevent undefined behavior and ensure predictable code execution. This includes specifying appropriate default values for configuration parameters and using platform-independent format specifiers for data types.

For configuration defaults, be explicit about expected values even when they seem obvious:
```cpp
// Good: Explicit defaults prevent undefined states
{"UptimeOffroad", {PERSISTENT, FLOAT, "0.0"}},
{"UptimeOnroad", {PERSISTENT, FLOAT, "0.0"}},
```

For type formatting, use portable macros to ensure correct behavior across platforms:
```cpp
// Good: Type-safe formatting prevents undefined behavior
LOGE("SV_ID != SLOT_NUMBER: %d %" PRIu64, msg->sv_id(), data->n());

// Alternative: Explicit casting for clarity
LOGE("SV_ID != SLOT_NUMBER: %d %llu", msg->sv_id(), (unsigned long long)data->n());
```

This approach prevents subtle bugs from implicit assumptions about default values or platform-specific type representations, ensuring consistent behavior across different environments and reducing the risk of undefined states.