openai/codex · error

WriteFile returned success but wrote 0 bytes

Error message

WriteFile returned success but wrote 0 bytes

What it means

Error "WriteFile returned success but wrote 0 bytes" thrown in openai/codex.

Source

Thrown at codex-rs/windows-sandbox-rs/src/unified_exec/backends/legacy.rs:230

fn write_all_handle(handle: HANDLE, mut bytes: &[u8]) -> Result<()> {
    while !bytes.is_empty() {
        let mut written = 0u32;
        let ok = unsafe {
            WriteFile(
                handle,
                bytes.as_ptr() as *const _,
                bytes.len() as u32,
                &mut written,
                ptr::null_mut(),
            )
        };
        if ok == 0 {
            let err = unsafe { GetLastError() } as i32;
            return Err(anyhow::anyhow!("WriteFile failed: {err}"));
        }
        if written == 0 {
            anyhow::bail!("WriteFile returned success but wrote 0 bytes");
        }
        bytes = &bytes[written as usize..];
    }
    Ok(())
}

#[allow(clippy::too_many_arguments)]
fn finalize_exit(
    exit_tx: oneshot::Sender<i32>,
    process_handle: Arc<StdMutex<Option<HANDLE>>>,
    thread_handle: HANDLE,
    output_join: std::thread::JoinHandle<()>,
    logs_base_dir: Option<&Path>,
    command: Vec<String>,
) {
    let exit_code = {
        let mut raw_exit = 1u32;
        if let Ok(guard) = process_handle.lock()

View on GitHub (pinned to 339751715c)

Solutions

1. Retry the write; a zero-byte successful write usually means the pipe buffer is full, so ensure the reader side is draining.

When it happens

Trigger: Thrown at codex-rs/windows-sandbox-rs/src/unified_exec/backends/legacy.rs:230 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of openai/codex@339751715c (2026-08-25). Data as JSON: /api/errors/1263f3614095bbf6. Report an issue: GitHub.