Added preliminary Linux support

Updated README

CITATION.cff

@@ -8,6 +8,6 @@ authors:
     given-names: Mahnaz
     orcid: https://orcid.org/0000-0002-3520-1553
 title: "pylinkam"
-version: 1.2.2
+version: 1.2.3
 doi: 10.5281/zenodo.6758012
 date-released: 2022-06-27

README.md

@@ -12,11 +12,10 @@ We use a Linkam HFS600E-PB4 stage with T96 controller for gas sensing experiment
 ## Installation
 Note that the Linkam SDK binary files (`LinkamSDK_release.dll` or `LinkamSDK_debug.dll`) and the required license file (typically `Linkam.lsk`) are **not** distributed as part of this module.
 
-By default, the module will look for the Linkam SDK dll using the `$PATH` environment variable, appending the module directory before searching.
+By default, the module will look for the Linkam SDK binary using the `$PATH` environment variable via the `ctypes` module and will automatically append the module directory before searching.
 
-0. If necessary, rename `LinkamSDK.dll` (recent versions) to `LinkamSDK_release.dll`
-1. Place `LinkamSDK_release.dll` (or `LinkamSDK_debug.dll`) and `Linkam.lsk` files inside the `pylinkam` module folder (the one that contains `__init__.py`). Alternately, at runtime you can specify a path to access these files.
-2. Run `demo.py` to check for any issues. This will set the stage temperature to 25°C temporarily.
+1. Place `LinkamSDK.dll` (debug or release) and `Linkam.lsk` files inside the `pylinkam` module folder (the one that contains `__init__.py`). Alternately, at runtime you can specify a binary name (remove the `.dll` extension on Windows) and path to access these files.
+2. Run `demo.py` to check for any connection/path issues. This will set the stage temperature to 25°C temporarily.
 
 ## Usage
 Initialise the SDK by creating an instance of `pylinkam.sdk.SDKWrapper` providing optional paths for SDK binary files and the license file. Once initialised, use the `connect()` method to create a context manager for the connection to a device.  
@@ -43,18 +42,18 @@ This library has been developed for the following Linkam instruments/addons, a c
 - [x] RH95 Humidity Controller
 - [ ] LNP96 Cooling Option (should work)
 
-Note that connecting multiple devices to a single host is also untested.
+Note that connecting multiple devices to a single host is untested, though the connect functions per the Linkam API *can* accept a serial number.
 
 ## Tested API Versions and Platforms
 
 - [x] `v3.0.5.5` on Windows 10
 - [x] `v3.0.15.35` on Windows 10
 
-In theory the SDK binary files for Linux should have identical mappings, but this hasn't been tested.
+In theory the SDK binary files for Linux should have identical mappings, but this hasn't been tested. Versions `< 1.2.3` used `WinDLL` to load the Linkam SDK binary, however more recent versions will automatically detect the platform and use `CDLL` when not on Windows. We don't have hardware connected to a Linux machine to test, so please report any issues.
 
 ## Acknowledgments
 
-Developed at [Swinburne University of Technology](https://swin.edu.au). If used in an academic project, please consider citing this work as it helps attract funding and track research outputs:
+Developed at [Swinburne University of Technology](https://swin.edu.au). If used in an academic or research project, please consider citing this work as it helps attract funding and track research outputs:
 
 ```
 C. J. Harrison and M. Shafiei. pylinkam. (2022). [Online]. doi: https://doi.org/10.5281/zenodo.6758012

pylinkam/__init__.py

@@ -1,5 +1,5 @@
 __app_name__ = 'pylinkam'
-__version__ = '1.2.2'
+__version__ = '1.2.3'
 
 __author__ = 'Chris Harrison'
 __credits__ = [__author__]

pylinkam/sdk.py

@@ -37,8 +37,14 @@ class ControllerConnectError(Exception):
 class SDKWrapper:
     """ Wrapper for Linkam SDK. """
 
+    # Assume SDK files are in the library root, can be overriden at instantiation
     _DEFAULT_SDK_ROOT_PATH = os.path.dirname(os.path.abspath(__file__))
 
+    _DEFAULT_BIN_NAME_LINUX = 'libLinkamSDK.so'
+
+    # Strip the .dll suffix, this is re-added automatically
+    _DEFAULT_BIN_NAME_WINDOWS = 'LinkamSDK'
+
     class Connection:
         """ Wrapper for connection to Linkam controller. """
 
@@ -331,22 +337,29 @@ def set_value(self, value_type: interface.StageValueType, n: typing.Any) -> bool
                 comm_handle=self._handle
             ))
 
-    def __init__(self, sdk_root_path: typing.Optional[str] = None, sdk_log_path: typing.Optional[str] = None,
-                 sdk_license_path: typing.Optional[str] = None, debug: bool = False):
+    def __init__(self, sdk_root_path: typing.Optional[str] = None, sdk_bin_name: typing.Optional[str] = None,
+                 sdk_log_path: typing.Optional[str] = None, sdk_license_path: typing.Optional[str] = None):
         """ Initialise the SDK, loading the required binary files.
 
         :param sdk_root_path: search path for SDK binary files, defaults to module directory
+        :param sdk_bin_name: SDK binary name (on Windows remove .dll extension), defaults to platform-dependant name
         :param sdk_log_path: path for SDK logging, defaults to SDK directory
         :param sdk_license_path: path for SDL license file, defaults to SDK directory
-        :param debug: if True use debug DLL, else use release version
         """
         self._sdk_root_path = sdk_root_path or self._DEFAULT_SDK_ROOT_PATH
 
-        self._sdk: typing.Optional[ctypes.WinDLL] = None
+        self._sdk: typing.Optional[ctypes.CDLL] = None
         self._sdk_lock = threading.RLock()
 
         # Setup DLL name and paths
-        self._sdk_dll_name = f"LinkamSDK_{'debug' if debug else 'release'}.dll"
+        if sdk_bin_name is None:
+            if os.name == 'nt':
+                self._sdk_bin_name = self._DEFAULT_BIN_NAME_WINDOWS
+            else:
+                self._sdk_bin_name = self._DEFAULT_BIN_NAME_LINUX
+        else:
+            self._sdk_bin_name = sdk_bin_name
+
         self._sdk_log_path = sdk_log_path or os.path.join(self.sdk_root_path, 'Linkam.log')
         self._sdk_license_path = sdk_license_path or os.path.join(self.sdk_root_path, 'Linkam.lsk')
 
@@ -362,14 +375,18 @@ def close(self) -> None:
         self._sdk = None
 
     @property
-    def sdk(self) -> ctypes.WinDLL:
+    def sdk(self) -> ctypes.CDLL:
         if self._sdk is None:
-            # Load SDK DLL
+            if os.name == 'nt':
+                loader: typing.Type[ctypes.CDLL] = ctypes.WinDLL
+            else:
+                loader = ctypes.CDLL
+
             try:
-                sdk = ctypes.WinDLL(self.sdk_dll_name)
+                sdk = loader(self.sdk_bin_name)
             except FileNotFoundError:
-                # Try absolute path
-                sdk = ctypes.WinDLL(os.path.join(self.sdk_root_path, self.sdk_dll_name))
+                # Re-attempt as an absolute path
+                sdk = loader(os.path.join(self.sdk_root_path, self.sdk_bin_name))
 
             if sdk is None:
                 raise SDKError('Linkam SDK was not loaded')
@@ -418,8 +435,8 @@ def sdk(self) -> ctypes.WinDLL:
         return self._sdk
 
     @property
-    def sdk_dll_name(self) -> str:
-        return self._sdk_dll_name
+    def sdk_bin_name(self) -> str:
+        return self._sdk_bin_name
 
     @property
     def sdk_license_path(self) -> str:
@@ -572,8 +589,8 @@ def _connect_serial(self, port: str) -> Connection:
         # Configure serial connection
         comm_info = interface.CommsInfo()
 
-        port = ctypes.create_string_buffer(port.encode())
-        self.sdk.linkamInitialiseSerialCommsInfo(ctypes.pointer(comm_info), port)
+        port_enc = ctypes.create_string_buffer(port.encode())
+        self.sdk.linkamInitialiseSerialCommsInfo(ctypes.pointer(comm_info), port_enc)
 
         return self._connect_common(comm_info)
 
@@ -587,9 +604,11 @@ def _connect_usb(self, serial_number: typing.Optional[str] = None) -> Connection
         comm_info = interface.CommsInfo()
 
         if serial_number is not None:
-            serial_number = ctypes.create_string_buffer(serial_number.encode())
+            serial_number_enc = ctypes.create_string_buffer(serial_number.encode())
+        else:
+            serial_number_enc = None
 
-        self.sdk.linkamInitialiseUSBCommsInfo(ctypes.pointer(comm_info), serial_number)
+        self.sdk.linkamInitialiseUSBCommsInfo(ctypes.pointer(comm_info), serial_number_enc)
 
         return self._connect_common(comm_info)