I come from a C# background and I am working on a C++ project. I need to open files in a directory, then process that data in the files. The problem is on my target environment (Greenhills Integrity), I cannot access a "directory". It seems C++ does not have a concept of a directory. Why not? This problem is simple in C#. I cannot link to any big library(BOOST or dirent) to get the files. I can open a file using fopen, but I won't always know the file names, so I have to "strcat" the directory to each filename in order to "fopen" the files.
I need a way to just get the file names in a directory without using an external API. Is that possible?
The major C++ APIs have directories. Start with readdir on POSIX or FindFirstFile() on Windows. Greenhills seems to support POSIX.
No, it's not possible. C++ has no "built-in" directory functionality - you need to use a library of some sort.
Check with your operating system. Directory handling is different for each. You will have to use the Windows 32 API if you want to list/query directories on Microsoft Windows, and the Linux API (e.g. opendir/stat) if you want to list/query directories on Linux.
Related
I am looking for a way to get the file names of files in a specific folder. I have search and many people say they use the boost.filesystem. I do not know how to include this in my c++ file/package to be able to use it, or ever how to use it. Is there a different method that might have been implemented. I am using Visual Studio for building my C++ program.
It would also need to be able to prompt the user folder specific folder/file.
One API available on almost all platforms is opendir()/readdir():
Open directory using C
DOS programs used findfirst()/findnext()/findclose(), followed by FindFirst()/FindNext() in Win32:
http://stanislavs.org/helppc/findfirst.html
http://msdn.microsoft.com/en-us/library/zyzxfzac.aspx
http://msdn.microsoft.com/en-us/library/windows/desktop/aa364418%28v=vs.85%29.aspx
I am trying to create file in main directory of operation system(for example Windows in my "c" disk) using c++.
Is there any better way than iterating all disks and search for "Windows" folder? Also its similar in mac and linux?
In Windows, you can call GetWindowsDirectory function (link). In Linux and Mac (I think), there's no such thing as main system directory.
However, as David noted, you should not put any files there:
This function is provided primarily for compatibility with legacy applications. New applications should store code in the Program Files folder and persistent data in the Application Data folder in the user's profile. For more information, see ShGetFolderPath.
I'm new to c++ and am trying to alter the console app code posted below to read multiple files, ideally using a wildcard extension. Can some please give me some pointers..?
http://msdn.microsoft.com/en-us/library/ms916815#odc_wssusageeventlogging_examiningtheusagelogfileformat
-----------Edit-------
What I need is how to change the code above instead of pointing it to a specific [filename.log] point it to a directory name and let it process all the log files in that directory.
--------------Tools-----
Win32 Console Application project in Visual Studio 2010 in C++
[To be run on win 32 bit platform]
Using Win32 APIs you can list the files in a directory by following this example. From there it should be relatively trivial for you to incorporate that code into your application to allow you to process multiple files as requested.
Specifically the FindFirstFile API allows for wildcard when search for files.
If you're willing to use the boost library check out
this post. If you're using something like C++/CLI then there is support in .NET for this as well (I'm assuming for now you're not using C++/CLI). If you specify the tools at your disposal maybe you can get a more directed answer.
Is there a standard place to store configurations like database setting in c++? Just use xml file?
Need windows solution, but it is better to be platform independent.
Check out Boost Program Options. Apart from being one of the best command-line option processors in any language, it also supports reading configuration data from files with a syntax like INI, and using environment variables. It's suitable for exactly what it says: program options. If you have a huge variety or a hierarchy of configurations, however, you might better check out Boost Property Tree, which read INI files but also XML or JSON, and is probably better suited if you have a really large configuration.
No standard that I know of, but you have several libraries for program configuration, for example libconfig. Also, the Windows API has some utilities to parse INI files for programs, for example see this link.
Standard C++ is a language only, it don't know anything other than the language itself.
What you're asking totally depends on the libraries or framework you'll decide to use to connect to databases. There is no standard library that have this purpose. So first choose the database, then the library to connect to it, then you'll get the configuration infos in the library documentation.
There's nothing in the standard, but Boost.Program_options is a good library for retrieving/storing configuration.
Obviously the configuration file must be stored in the correct location: if it's a per-user configuration file, on Windows it will be stored in the %APPDATA%1 directory (usually in a subdirectory named after your application), on Linux in a dot file under the home directory. For non-user specific configuration files, they may be stored in the "All Users" Application Data folder on Windows1, and under /etc on Linux2.
Naturally, you won't hardcode these paths, but you'll use SHGetFolderPath with the appropriate CSIDL values (or SHGetKnownFolderPath if you don't care about pre-Vista compatibility), like CSIDL_APPDATA for per-user settings, CSIDL_COMMON_APPDATA for settings common to all users.
Notice that /etc on Linux is writeable only by the superuser; I don't remember if the "all users" profile is writable for normal users under Windows.
Are there any cross platform libraries that will help me place certain file in different directories. For example in windows a config file will probably go in app data, yet in Linux it will go in /etc/ or /use/etc/ depending on where it was installed. Is there any way to do this transparently?
boost::filesystem will should soon provide such functionalities (but not yet). I would be you, I'd use boost::filesystem and provide different addresses of user folders by platforms, then when boost::filesystem provide the feature, replace the implementations.
Did you try with Qt libraries?
Both QFileInfo( qApp->argv()[0] )::absFilePath ()
and QApplication::applicationDirPath() can work.