# error.Error.invalid_version_output_len

- **Module:** error.Error
- **Package:** libtmux
- **Language:** Rust
- **Kind:** method
- **Source:** https://github.com/libtmux/libtmux-rs/blob/f0e37052c232636b61d095817046e6bfc8f2ca40/crates/libtmux/src/error.rs#L1340
- **Page:** https://libtmux.org/en/rs/latest/reference/error-error-invalid_version_output_len/

```
error.Error.invalid_version_output_len(self) -> Option<usize>
```

Return the length of the invalid `tmux -V` output, when present.

The error never retains the process output itself.

## Example

```rust
use libtmux::TmuxVersion;

let output = b"invalid\n";
let error = TmuxVersion::parse_output(output).expect_err("output is invalid");
assert_eq!(error.invalid_version_output_len(), Some(output.len()));
```