build: link windows-native driver when targeting windows

This is completely experimental, but since the API is the same, it's a
drop-in replacement. The Windows driver is not apparently open source,
so I am vendoring the static libraries provided. In theory, this will
obviate the need to replace the HID driver on Windows and will thus
require no initial setup, but I cannot currently test it beyond making
sure it compiles.

build.zig

@@ -17,11 +17,21 @@ pub fn build(b: *std.Build) void {
         .optimize = optimize,
     });
 
+    if (target.result.os.tag == .windows) {
+        if (target.result.cpu.arch == .x86)
+            exe.addObjectFile(b.path("deps/labjack/windows/ljackuw32.lib"))
+        else if (target.result.cpu.arch == .x86_64)
+            exe.addObjectFile(b.path("deps/labjack/windows/ljackuw64.lib"))
+        else
+            @panic("Unsupported CPU arch for Windows build (must be x86 or x86_64).");
+    } else {
         const ljacklm_dep = b.dependency(
             "ljacklm",
             .{ .target = target, .optimize = optimize, .use_udev = use_udev },
         );
         exe.linkLibrary(ljacklm_dep.artifact("ljacklm"));
+    }
+
     exe.root_module.addImport(
         "udev_rules",
         b.addModule("udev_rules", .{

src/labjack.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const builtin = @import("builtin");
 
 pub fn getDriverVersion() f32 {
     return c_api.GetDriverVersion();
@@ -289,6 +290,11 @@ pub const PackedOutput = packed struct(u4) {
     }
 };
 
+const Call: std.builtin.CallingConvention = if (builtin.os.tag == .windows and builtin.cpu.arch == .x86)
+    .Stdcall
+else
+    .C;
+
 pub const c_api = struct {
     pub const vendor_id: u16 = 0x0CD5;
     pub const u12_product_id: u16 = 0x0001;
@@ -300,9 +306,9 @@ pub const c_api = struct {
         idnum: *c_long,
         serialnum: *c_long,
         caldata: *[20]c_long,
-    ) c_long;
+    ) callconv(Call) c_long;
 
-    pub extern fn CloseAll(local_id: c_long) c_long;
+    pub extern fn CloseAll(local_id: c_long) callconv(Call) c_long;
 
     pub extern fn GetU12Information(
         handle: *anyopaque,
@@ -312,7 +318,7 @@ pub const c_api = struct {
         cal_data: *[20]c_long,
         fcdd_max_size: *c_long,
         hvc_max_size: *c_long,
-    ) c_long;
+    ) callconv(Call) c_long;
 
     pub extern fn EAnalogIn(
         idnum: *c_long,
@@ -321,14 +327,14 @@ pub const c_api = struct {
         gain: c_long,
         overVoltage: *c_long,
         voltage: *f32,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn EAnalogOut(
         idnum: *c_long,
         demo: c_long,
         analogOut0: f32,
         analogOut1: f32,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn ECount(
         idnum: *c_long,
@@ -336,7 +342,7 @@ pub const c_api = struct {
         resetCounter: c_long,
         count: *f64,
         ms: *f64,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn EDigitalIn(
         idnum: *c_long,
@@ -344,7 +350,7 @@ pub const c_api = struct {
         channel: c_long,
         readD: c_long,
         state: *c_long,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn EDigitalOut(
         idnum: *c_long,
@@ -352,7 +358,7 @@ pub const c_api = struct {
         channel: c_long,
         writeD: c_long,
         state: c_long,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn AsynchConfig(
         idnum: *c_long,
@@ -367,7 +373,7 @@ pub const c_api = struct {
         halfA: c_long,
         halfB: c_long,
         halfC: c_long,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn Asynch(
         idnum: *c_long,
@@ -380,7 +386,7 @@ pub const c_api = struct {
         numWrite: c_long,
         numRead: c_long,
         data: [*]c_long,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn AISample(
         idnum: *c_long,
@@ -394,7 +400,7 @@ pub const c_api = struct {
         disableCal: c_long,
         overVoltage: *c_long,
         voltages: *[4]f32,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn AIBurst(
         idnum: *c_long,
@@ -415,7 +421,7 @@ pub const c_api = struct {
         stateIOout: *[4096]c_long,
         overVoltage: *c_long,
         transferMode: c_long, // 0=auto,1=normal,2=turbo
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn AIStreamStart(
         idnum: *c_long,
@@ -430,7 +436,7 @@ pub const c_api = struct {
         disableCal: c_long,
         reserved1: c_long, // always 0
         readCount: c_long,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn AIStreamRead(
         localID: c_long,
@@ -441,11 +447,11 @@ pub const c_api = struct {
         reserved: ?*c_long, // unused
         ljScanBacklog: *c_long,
         overVoltage: *c_long,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn AIStreamClear(
         localID: c_long,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn AOUpdate(
         idnum: *c_long,
@@ -459,21 +465,21 @@ pub const c_api = struct {
         count: [*c]c_ulong,
         analogOut0: f32,
         analogOut1: f32,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn BitsToVolts(
         chnum: c_long,
         chgain: c_long,
         bits: c_long,
         volts: [*c]f32,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn VoltsToBits(
         chnum: c_long,
         chgain: c_long,
         volts: f32,
         bits: [*c]c_long,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn Counter(
         idnum: *c_long,
@@ -483,7 +489,7 @@ pub const c_api = struct {
         resetCounter: c_long,
         enableSTB: c_long,
         count: [*c]c_ulong,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn DigitalIO(
         idnum: *c_long,
@@ -494,12 +500,12 @@ pub const c_api = struct {
         stateIO: *c_long, // 4 bits
         updateDigital: c_long,
         outputD: *c_long, // 16 bits
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
-    pub extern fn GetDriverVersion() f32;
+    pub extern fn GetDriverVersion() callconv(Call) f32;
-    pub extern fn StaticErrorString(errorcode: c_long) [*:0]const u8;
+    pub extern fn StaticErrorString(errorcode: c_long) callconv(Call) [*:0]const u8;
-    pub extern fn GetErrorString(errorcode: c_long, errorString: *[50]u8) void;
+    pub extern fn GetErrorString(errorcode: c_long, errorString: *[50]u8) callconv(Call) void;
-    pub extern fn GetFirmwareVersion(idnum: *c_long) f32;
+    pub extern fn GetFirmwareVersion(idnum: *c_long) callconv(Call) f32;
 
     pub extern fn ListAll(
         productIDList: *[127]c_long,
@@ -510,12 +516,12 @@ pub const c_api = struct {
         numberFound: *c_long,
         fcddMaxSize: *c_long,
         hvcMaxSize: *c_long,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn LocalID(
         idnum: *c_long,
         localID: c_long,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn PulseOut(
         idnum: *c_long,
@@ -527,7 +533,7 @@ pub const c_api = struct {
         timeC1: c_long,
         timeB2: c_long,
         timeC2: c_long,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn PulseOutStart(
         idnum: *c_long,
@@ -539,24 +545,24 @@ pub const c_api = struct {
         timeC1: c_long,
         timeB2: c_long,
         timeC2: c_long,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn PulseOutFinish(
         idnum: *c_long,
         demo: c_long,
         timeoutMS: c_long,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn PulseOutCalc(
         frequency: *f32,
         timeB: *c_long,
         timeC: *c_long,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
-    pub extern fn ReEnum(idnum: *c_long) LabjackCError;
+    pub extern fn ReEnum(idnum: *c_long) callconv(Call) LabjackCError;
-    pub extern fn Reset(idnum: *c_long) LabjackCError;
+    pub extern fn Reset(idnum: *c_long) callconv(Call) LabjackCError;
-    pub extern fn ResetLJ(idnum: *c_long) LabjackCError;
+    pub extern fn ResetLJ(idnum: *c_long) callconv(Call) LabjackCError;
-    pub extern fn CloseLabJack(localID: c_long) LabjackCError;
+    pub extern fn CloseLabJack(localID: c_long) callconv(Call) LabjackCError;
 
     pub extern fn SHT1X(
         idnum: *c_long,
@@ -567,7 +573,7 @@ pub const c_api = struct {
         tempC: *f32,
         tempF: *f32,
         rh: *f32,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn SHTComm(
         idnum: *c_long,
@@ -579,7 +585,7 @@ pub const c_api = struct {
         numRead: c_long,
         datatx: [*]u8, // numWrite length
         datarx: [*]u8, // numRead length
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn SHTCRC(
         statusReg: c_long,
@@ -587,7 +593,7 @@ pub const c_api = struct {
         numRead: c_long,
         datatx: *[4]u8,
         datarx: *[4]u8,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn Synch(
         idnum: *c_long,
@@ -601,7 +607,7 @@ pub const c_api = struct {
         configD: c_long,
         numWriteRead: c_long,
         data: *[18]c_long,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn Watchdog(
         idnum: *c_long,
@@ -615,7 +621,7 @@ pub const c_api = struct {
         stateD0: c_long,
         stateD1: c_long,
         stateD8: c_long,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn ReadMem(
         idnum: *c_long,
@@ -624,7 +630,7 @@ pub const c_api = struct {
         data2: *c_long,
         data1: *c_long,
         data0: *c_long,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub extern fn WriteMem(
         idnum: *c_long,
@@ -634,7 +640,7 @@ pub const c_api = struct {
         data2: c_long,
         data1: c_long,
         data0: c_long,
-    ) LabjackCError;
+    ) callconv(Call) LabjackCError;
 
     pub const LabjackCError = packed struct(c_ulong) {
         code: LabjackErrorCode,