esp8266/Arduino

Functions / symbols defined in sketch may override framework .a

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#8,710 opened on Nov 6, 2022

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component: corehelp wanted

Description

I tested the MCVE and OTA works again perfectly fine. I found the problem in my full sketch. I had a global object called crc32! The same name as the function name with problem. Sorry for bothering you and thank you @earlephilhower for your help. Closing this issue...

Originally posted by @kamran00f in https://github.com/esp8266/Arduino/issues/7651#issuecomment-707327428

Contributor guide

Tech stack
cpp
Domain
tooling
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
basic C++ knowledgeArduino IDE familiarityESP8266 sketch structure
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Investigate how the ESP8266 Arduino core's build system handles symbol conflicts between user sketches and precompiled libraries (.a files). The issue mentions a global variable named 'crc32' overriding a framework function; examine the linking order and possible use of weak symbols. Look at the core's platform.txt or linker scripts to understand how symbols are resolved, and check if there is a need to prevent user symbols from overriding internal ones (e.g., using C++ namespaces or prefixing). Refer to the issue comment at https://github.com/esp8266/Arduino/issues/7651#issuecomment 707327428 for the user's self resolution.