boost::program_options conditionally required option - c++

My executable has two modes of operation which are selectable via --mode=foo or --mode=bar. If mode=foo, then --abc option should be required and --xyz should not be specified. If mode=bar, then --xyz option should be required and --abc should not be specified. What is the correct way to code that?

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How can I get the logging directory of a RollingFileAppender from log4cxx?

I'm using XML to configure log4cxx. The appender is a RollingFileAppender that outputs to a folder like yyyy/MM/dd/HHmm, and I need to know what that folder is at the end of the program.
I can't get the current yyyy/MM/dd/HHmm at runtime because that value will likely be different than it was when the log directory was created. After scanning log4cxx's documentation, I found only one function that was relevant:
log4cxx::FileAppender::getFile()
which returns the file that an appender is logging to.
The problem with that is that calls to log4cxx::Logger::getAppender() yield only AppenderPtrs- I could dynamic_cast this into a FileAppender if I know that's the ultimate type, but this introduces uncertainty into the program. Is there really no way to get the current log directory from log4cxx?
Thanks!
There is currently no(easy) way to get the name of the file that the RollingFileAppender is using.
Using Logger::getAppender() is the best way to get the correct appender that you are looking for. Since the appenders should all have unique names, there shouldn't be any issue with casting to the correct type. If you want to be safe about casting, use log4cxx::cast<FileAppender>( AppenderPtr ) which will return an invalid pointer if the object is unable to be casted to the correct type.

how to change gmock verbosity level

I want to change gmock warnings into errors in all uninteresting gmock function calls.
I search some and I found that i should use --gmock_verbose=LEVEL flag but where should I add this flag?
Unfortunately I couldn't change all NiceMocks to StrictMocks.
where should I add this flag?
You can add gmock flags like --gmock_verbose=error directly in the command line.
Otherwise, you can always specify verbosity on a per test basis by putting ::testing::FLAGS_gmock_verbose = "error"; in the test code itself.
Source: http://google.github.io/googletest/gmock_cook_book.html#controlling-how-much-information-gmock-prints

How can I debug a C++ DLL function, called from VBA, using Visual Studio

I have written a DLL function in C++, which I am calling from VBA (Excel).
How can I setup the Visual Studio properties to allow me to debug the function? I have tried specifying Excel, but that doesn’t seem to work.
You have two choices: "direct debug", or "attach".
I strongly prefer the "direct debug" approach for a long list of reasons omitted from here.
There are steps required on both the DLL and Excel/VBA sides, your posting is unclear if all of those steps are addressed.
There are variations on the following:
1) In VS, depending on the version, enter Project Settings, or Project Properties, or equivalent, in the "Debug (not release) Target", go to the Debug or Debugging settings. :
a) There will be an field called "Executable for debugging session", or "command", or something like that depending on VS ver. Here, enter the full path of your Excel exe
b) Optionally, if the same "test spread sheet" is used frequently, enter the full path of your xls (or whatever) in the field called "Command argument", or "program argument" or as in your VS ver.
You may need to surround this with double quotes (e.g. if there are spaces in your path/file names).
c) You can also set the output of your project to a Dir that is "addin helpful", such as a Dir called AddIn (c.f. having the DLL end up in Debug (or Release) Dirs)
... it is assumed that your DLL has all the bits required to export the functions, with the project being of type DLL, plus any DLLEXPORT and compiler directives, etc etc.
... the specifics of the DLLEXPORT settings (and related compiler switches) and Calling Convention will determine many things ... it is assumed you have done all that correctly and consistently (and especially consistently with what the Excel-side is expecting).
... your DLL may or may not have a DLL_Main, if it does, more discussion is required.
2) Before anything else, be sure to have created the Excel-side "interface" for your DLL, ie. the "Add-In". This can be either via .xla, or via .xll. I strongly suggest the .xla route as your first approach.
See the Excel help files etc for creating the .xla
Then, in your XLA's VBA Module(s), declare the functions/subs etc from your DLL. For example, if you have a DLL called Add2_DLL.dll, which contains an exported function "add2_pho_xl", then:
Public Declare Function Add2_Pho_XX Lib "E:\EclipseWorkSpace\Add2_DLL\Debug\Add2_DLL.dll" _
Alias "add2_pho_xl" (A As Double, B As Double) As Double
I have used the Alias approach here, for reasons required below.
In many instances, this declaration can be used directly as User Defined Function (UDF) in your sheets, etc. However, for a vast number of cases, you will need to create a VBA "spinner" function/sub that creates the "ultimate" UDF, and relies on this direct entry function (see below). This is also a very long story, but necessary where more complex matters are required (arrays, variants, etc etc).
NOTICE:
a) the DLL's full path is required unless special steps have been taken. If your Addin is for general distribution ... a much longer discussion is required.
b) the Alias must be the EXACT entry name of the function in your DLL. If you view near the end of the DLL (or .Def) files, and unless you set your DLL modules as Private, those will show the entry names expected on the DLL side.
In this example, the entry name is NOT "decorated" due to the choices in the Calling Convention and compiler switches, but it could look something like
"_add2_pho_xl_#08" etc depending your choices.
... in any case, you must use whatever the DLL has.
3) Once both the .xla and dll exist (it is best if they are in the same Dir), Excel must be "told" about the Add-In. The easiest approach is Excel/Tools/Addins, but there are various strategies for "registering" DLL functions.
4) CRUCIALLY, the argument list properties/declarations MUST BE CONGRUENT with BOTH those in your DLL and the Calling Convention. Three (of many possible) examples of "issues" are,
(i) A Boolean on the VBA-side is two-bytes, if the Bool/Logical on your DLL side is 1-byte, then the Debug will fail, since the two sides "cannot connect" properly.
(ii) Strings ... this can be a very long story. It depends if sent ByVal or ByRef, it depends if the DLL side has "hidden length" Args, etc. etc. Remember, VBA uses COM/OLE VBStrings, which have their own can of worms.
(iii) Variants/Objects: these require a tome onto themselves
5) If ALL (and likely more) of the above have gone well, then in VS set your break points, if required, and "Go" or "Start" the debug (depending on VS ver, etc.). This should launch Excel, and if you also set the target xls, it will launch too. Go to the cell(s) where you addin function (e.g. =add2_pho_XX(A1, B1) ) resides, and execute the cell (sometimes using the "fx" menu item is useful, but there are other ways also).
Some hints:
a) if the func execution crashes/hangs etc Excel and does not even arrive back to the VS side, then likely there is a Arg list conflict (e.g. you are passing a Double to an Int or a million other possibilities), or Calling Convention conflict, etc.
b) In general, you may (while in the VS debug session) simultaneously perform a VBA debug session. That is, after starting the VS bebug, entre the VBA IDE, and set break points in VBA UDF's, if a "spinner" UDF's have been created. For example, a VBA UDF that relies also on the DLL's function.
Private Function Add2_Pho( FirstNum as Double, SecondNum as Double, Optional lMakeRed as Variant) As Variant
'
'
Add2_Pho = Add2_Pho_XX( FirstNum, SecondNum ) ' this is the actual DLL func accessed via Delcare above
'
If( IsMissing(lMakeRed) ) Then
Else
If( cBool(lMakeRed) ) Then
If( Add2_Pho < 0 ) Then
'
' ' make the result Red, or something
'
End If
End If
End If
'
'
End Function
... here, setting a break point at the first line can be helpful to see if the UDF is even entered on the VBA side. If it is, click Continue in VBA, and see if it makes it to the VS side, if not, check Args, Calling Convention, etc again, etc etc
c) If the cell's content are #Value or some other unexpected result, then at least the UDF is "recognised" but not functioning correctly, either due to sheet->VBA issues, or VBA-> DLL issues, or after the return DLL-> VBA
d) Save often! and Use the VBA IDE's Debug/ Compile VBA Project before running anything just make sure VBA internal consistency.
e) Also, if you are using VBA/XLA's, then get a copy of CleanProject (VBA can mess up its internals sometimes, and this Tool will be a life saver)
Please make sure that Debug mode is the active mode.
How to debug your DLL with Excel/VBA

Boost program options with default values always present when using vm.count()

I've been trying to validate my passed options with boost::program_options. My command has several modes, each of which have associated params that can be specified. What I'm trying to do is ensure these associated params are passed with the mode, i.e.
unicorn --fly --magic-wings-threshold
Where --fly is the mode and --magic-wings-threshold is an associated param. What I've noticed is if --magic-wings-threshold has a default value, e.g.
("magic-wings-threshold,w", po::value<double>(&wings_thresh)->default_value(0.8, "0.8"),
"Magic wings maximum power"
)
then I can't use
if (vm.count("magic-wings-threshold")( {
// do stuff
}
to detect if the user passed that param.
It appears that default value params are always passed and detected in vm.count(). Does anyone know a workaround or alternative?
use boost::program_options::variable_value::defaulted()
if (vm["magic-wings-threshold"].defaulted()) {
// assume defaulted value
} else {
// one was provided
}
If you want to tell difference between
-k option not provided
-k provided
You should use po::value()->implicit_value(), You can tell the different situations with:
-k option not provided -> vm["k"]==0
-k option provided -> vm["k"]==1

Create registry entry to associate file extension with application in C++

I would like to know the cleanest way of registering a file extension with my C++ application so that when a data file associated with my program is double clicked, the application is opened and the filename is passed as a parameter to the application.
Currently, I do this through my wix installer, but there are some instances where the application will not be installed on ths user's computer, so I also need the option of creating the registry key through the application.
Additionally, will this also mean that if the application is removed, unused entries in the registry will be left lying around?
Your basic overview of the process is found in this MSDN article. The key parts are at the bottom of the list:
Register the ProgID
A ProgID (essentially, the file type registry key) is what contains your important file type properties, such as icon, description, and context menu items including applications used when the file is double clicked. Many extensions may have the same file type. That mapping is done in the next step:
Register the file name extension for the file type
Here, you set a registry value for your extension, setting that extension's file type to the ProgID you created in the previous step.
The minimum amount of work required to get a file to open with your application is setting/creating two registry keys. In this example .reg file, I create a file type (blergcorp.blergapp.v1) and associate a file extension (.blerg) with it.
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Classes\blergcorp.blergapp.v1\shell\open\command]
#="c:\path\to\app.exe \"%1\""
[HKEY_CURRENT_USER\Software\Classes\.blerg]
#="blergcorp.blergapp.v1"
Now, you probably want to accomplish this programmatically. To be absolutely kosher, you could check for the existence of these keys, and change your program behavior accordingly, especially if you're assuming control of some common file extension. However, the goal can be accomplished by setting those two keys using the SetValue function.
I'm not positive of the exact C++ syntax, but in C# the syntax looks something like this:
Registry.SetValue(#"HKEY_CURRENT_USER\Software\Classes\blergcorp.blergapp.v1\shell\open\command", null, #"c:\path\to\app.exe \"%1\"");
Registry.SetValue(#"HKEY_CURRENT_USER\Software\Classes\.blerg", null, "blergcorp.blergapp.v1");
Of course you could manually open each sub key, manually create the ProgID and extension subkey, and then set the key value, but a nice thing about the SetValue function is that if the keys or values don't exist, they will automatically be created. Very handy.
Now, a quick word about which hive to use. Many file association examples online, including ones on MSDN, show these keys being set in HKEY_CLASSES_ROOT. I don't recommend doing this. That hive is a merged, virtual view of HKEY_LOCAL_MACHINE\Software\Classes (the system defaults) and HKEY_CURRENT_USER\Software\Classes (the per-user settings), and writes to any subkey in the hive are redirected to the same key in HKEY_LOCAL_MACHINE\Software\Classes. Now, there's no direct problem doing this, but you may run into this issue: If you write to HKCR (redirected to HKLM), and the user has specified the same keys with different values in HKCU, the HKCU values will take precedence. Therefore, your writes will succeed but you won't see any change, because HKEY_CURRENT_USER settings take precedence over HKEY_LOCAL_MACHINE settings.
Therefore, you should take this into consideration when designing your application. Now, on the flip side, you can write to only HKEY_CURRENT_USER, as my examples here show. However, that file association setting will only be loaded for the current user, and if your application has been installed for all users, your application won't launch when that other user opens the file in Windows.
That should be a decent primer for what you want to do. For further reading I suggest
Best Practices for File Association
File Types and File Association, especially
How File Associations Work
And see also my similar answer to a similar question:
Associating file extensions with a program
This is a two step process:
1. Define a program that would take care of extension: (unless you want to use existing one)
1.1 create a key in "HKCU\\Software\\Classes\\" for example
"Software\\Classes\\YourProgramName.file.ext"
1.2 create subkey "Software\\Classes\\YourProgramName.file.ext\\DefaultIcon"
1.2.1 set default value ("") to your application full path to get
icon from resources
1.3 create a subkey "Software\\Classes\\YourProgramName.file.ext\\Shell\\OperationName\\Command"
OperationName = for example Open, Print or Other
1.3.1 set default value ("") to your application full path +optional runtime params (filename)
2.Associate file extension with program.
2.1 create a key HKCU\\Software\\Classes\\.ext - here goes your extension
2.2 set default value to the program definition key
("YourProgramName.file.ext")
Below is part of the program written in c# which associate file extension. It is not c++ but i think it is simple enought to explain itself and AFAIK it is verv simmilar if not identical to the code in c++
1.
RegistryKey keyPFCTExt0 = Registry.CurrentUser.OpenSubKey("Software\\Classes\\PFCT.file.enc", true);
if (keyPFCTExt0 == null)
{
keyPFCTExt0 = Registry.CurrentUser.CreateSubKey("Software\\Classes\\PFCT.file.enc");
keyPFCTExt0.CreateSubKey("DefaultIcon");
RegistryKey keyPFCTExt0ext = Registry.CurrentUser.OpenSubKey("Software\\Classes\\PFCT.file.enc\\DefaultIcon", true);
keyPFCTExt0ext.SetValue("", Application.ExecutablePath +",0");
keyPFCTExt0ext.Close();
keyPFCTExt0.CreateSubKey("Shell\\PFCT_Decrypt\\Command");
}
keyPFCTExt0.SetValue("", "PFCT.file.enc");
keyPFCTExt0.Close();
2.
RegistryKey keyPFCTExt1 = Registry.CurrentUser.OpenSubKey("Software\\Classes\\PFCT.file.enc\\Shell\\PFCT_Decrypt\\Command", true);
if (keyPFCTExt1 == null)
keyPFCTExt1 = Registry.CurrentUser.CreateSubKey("Software\\Classes\\PFCT.file.enc\\Shell\\PFCT_Decrypt\\Command");
keyPFCTExt1.SetValue("", Application.ExecutablePath + " !d %1"); //!d %1 are optional params, here !d string and full file path
keyPFCTExt1.Close();
I don't know why people keep saying that HKEY_CURRENT_USER\Software\Classes\<.ext>'s Default value (which will redirect you into another (software-created) class.
It does work, but it will be overridden by
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\<.ext>\UserChoice
And I believe Microsoft recommends the second practice- because it's what the built-in "open with" is doing. The value of Progid" key is equal to default value of HKEY_CURRENT_USER\Software\Classes\<.ext> in this case.
I found the following while trying to manipulate associations using C#:
hkcu\software\microsoft\windows\currentVersion\explorer\fileexts.reg\userchoice -> for user specific settings. The values in the openWithProgIds
key point to the keys in the hkcr.
hkcr\xfile\shell\open\muiVerb value or hkcr\xfile\shell\open\command\default value -> affects open handler. This is the value that contains the path to a program.
hkcr\ .x -> affects context menu (new x) among other things related to the menus.
I don't know the C++ code, but given these info you must be able to manipulate the registry using the registry API.