# visa-rs

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Safe Rust bindings for VISA(Virtual Instrument Software Architecture) library

Most documentation comes from [NI-VISA Product Documentation](https://www.ni.com/docs/en-US/bundle/ni-visa-20.0/page/ni-visa/help_file_title.html)

## Requirements

This crate needs to link to an installed visa library, for example, [NI-VISA](https://www.ni.com/en-us/support/downloads/drivers/download.ni-visa.html).

A default link configuration is used for the default installation setup on Windows, Linux and MacOs.  

You can overwrite the configuration by specifying the name of the visa library file (default to `visa` for linux, `visa64` or `visa32` for windows) by environment variable `LIB_VISA_NAME`, and the path of the file by environment variable `LIB_VISA_PATH`.

## Example

Codes below will find the first Keysight instrument in your environment and print out its `*IDN?` response.

```rust
fn find_an_instr() -> visa_rs::Result<()>{
  use std::ffi::CString;
  use std::io::{BufRead, BufReader, Read, Write};
  use visa_rs::prelude::*;

  // open default resource manager
  let rm: DefaultRM = DefaultRM::new()?;

  // expression to match resource name
  let expr = CString::new("?*KEYSIGH?*INSTR").unwrap().into();

  // find the first resource matched
  let rsc = rm.find_res(&expr)?;

  // open a session to the resource, the session will be closed when rm is dropped
  let instr: Instrument = rm.open(&rsc, AccessMode::NO_LOCK, TIMEOUT_IMMEDIATE)?;

  // write message
  (&instr).write_all(b"*IDN?\n").map_err(io_to_vs_err)?;

  // read response
  let mut buf_reader = BufReader::new(&instr);
  let mut buf = String::new();
  buf_reader.read_line(&mut buf).map_err(io_to_vs_err)?;

  eprintln!("{}", buf);
  Ok(())
}
```

License: MIT OR Apache-2.0