DioxusLabs/dioxus · error

Failed to find main symbol

Error message

Failed to find main symbol

What it means

On mobile, the desktop crate's injected root tried to locate the app's C entry point via dlsym for both "main" and "_main" and both lookups returned null. Without the main symbol pointer, the mobile runtime cannot hand off execution to the user's app.

Source

Thrown at packages/desktop/src/mobile.rs:77

        fn stop_unwind<F: FnOnce() -> T, T>(f: F) -> T {
            match std::panic::catch_unwind(std::panic::AssertUnwindSafe(f)) {
                Ok(t) => t,
                Err(err) => {
                    eprintln!("attempt to unwind out of `rust` with err: {:?}", err);
                    std::process::abort()
                }
            }
        }

        stop_unwind(|| unsafe {
            let mut main_fn_ptr = libc::dlsym(libc::RTLD_DEFAULT, b"main\0".as_ptr() as _);

            if main_fn_ptr.is_null() {
                main_fn_ptr = libc::dlsym(libc::RTLD_DEFAULT, b"_main\0".as_ptr() as _);
            }

            if main_fn_ptr.is_null() {
                panic!("Failed to find main symbol");
            }

            // Set the env vars that rust code might expect, passed off to us by the android app
            // Doing this before main emulates the behavior of a regular executable
            if cfg!(target_os = "android") && cfg!(debug_assertions) {
                // Load the env file from the session cache if we're in debug mode and on android
                //
                // This is a slightly hacky way of being able to use std::env::var code in android apps without
                // going through their custom java-based system.
                let env_file = dioxus_cli_config::android_session_cache_dir().join(".env");
                if let Ok(env_file) = std::fs::read_to_string(&env_file) {
                    for line in env_file.lines() {
                        if let Some((key, value)) = line.trim().split_once('=') {
                            std::env::set_var(key, value);
                        }
                    }
                }
            }

View on GitHub (pinned to 24f6a829df)

Solutions

1. The mobile binary has no main symbol to call. Ensure the app exposes a main entry point and the mobile target links it correctly.

When it happens

Trigger: Thrown at packages/desktop/src/mobile.rs:77 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of DioxusLabs/dioxus@24f6a829df (2026-08-23). Data as JSON: /api/errors/5ddf133578e28678. Report an issue: GitHub.