Method SysGet

Source/script2.cpp:3877–4011

ResultType Line::SysGet(char *aCmd, char *aValue)
// Thanks to Gregory F. Hogg of Hogg's Software for providing sample code on which this function
// is based.
{
	// For simplicity and array look-up performance, this is done even for sub-commands that output to an array:
	Var *output_var = ResolveVarOfArg(0);
	if (!output_var)
		return FAIL;

	SysGetCmds cmd = ConvertSysGetCmd(aCmd);
	// Since command names are validated at load-time, this only happens if the command name
	// was contained in a variable reference.  But for simplicity of design here, return
	// failure in this case (unlike other functions similar to this one):
	if (cmd == SYSGET_CMD_INVALID)
		return LineError(ERR_SYSGET ERR_ABORT, FAIL, aCmd);

	MonitorInfoPackage mip = {0};  // Improves maintainability to initialize unconditionally, here.
	mip.monitor_info_ex.cbSize = sizeof(MONITORINFOEX); // Also improves maintainability.

	// EnumDisplayMonitors() must be dynamically loaded; otherwise, the app won't launch at all on Win95/NT.
	typedef BOOL (WINAPI* EnumDisplayMonitorsType)(HDC, LPCRECT, MONITORENUMPROC, LPARAM);
	static EnumDisplayMonitorsType MyEnumDisplayMonitors = (EnumDisplayMonitorsType)
		GetProcAddress(GetModuleHandle("user32.dll"), "EnumDisplayMonitors");

	switch(cmd)
	{
	case SYSGET_CMD_METRICS: // In this case, aCmd is the value itself.
		return output_var->Assign(GetSystemMetrics(ATOI(aCmd)));  // Input and output are both signed integers.

	// For the next few cases, I'm not sure if it is possible to have zero monitors.  Obviously it's possible
	// to not have a monitor turned on or not connected at all.  But it seems likely that these various API
	// functions will provide a "default monitor" in the absence of a physical monitor connected to the
	// system.  To be safe, all of the below will assume that zero is possible, at least on some OSes or
	// under some conditions.  However, on Win95/NT, "1" is assumed since there is probably no way to tell
	// for sure if there are zero monitors except via GetSystemMetrics(SM_CMONITORS), which is a different
	// animal as described below.
	case SYSGET_CMD_MONITORCOUNT:
		// Don't use GetSystemMetrics(SM_CMONITORS) because of this:
		// MSDN: "GetSystemMetrics(SM_CMONITORS) counts only display monitors. This is different from
		// EnumDisplayMonitors, which enumerates display monitors and also non-display pseudo-monitors."
		if (!MyEnumDisplayMonitors) // Since system only supports 1 monitor, the first must be primary.
			return output_var->Assign(1); // Assign as 1 vs. "1" to use hexidecimal display if that is in effect.
		mip.monitor_number_to_find = COUNT_ALL_MONITORS;
		MyEnumDisplayMonitors(NULL, NULL, EnumMonitorProc, (LPARAM)&mip);
		return output_var->Assign(mip.count); // Will assign zero if the API ever returns a legitimate zero.

	// Even if the first monitor to be retrieved by the EnumProc is always the primary (which is doubtful
	// since there's no mention of this in the MSDN docs) it seems best to have this sub-cmd in case that
	// policy ever changes:
	case SYSGET_CMD_MONITORPRIMARY:
		if (!MyEnumDisplayMonitors) // Since system only supports 1 monitor, the first must be primary.
			return output_var->Assign(1); // Assign as 1 vs. "1" to use hexidecimal display if that is in effect.
		// The mip struct's values have already initalized correctly for the below:
		MyEnumDisplayMonitors(NULL, NULL, EnumMonitorProc, (LPARAM)&mip);
		return output_var->Assign(mip.count); // Will assign zero if the API ever returns a legitimate zero.

	case SYSGET_CMD_MONITORAREA:
	case SYSGET_CMD_MONITORWORKAREA: