Question

Like the title says; how do I load every file in a directory? I’m interested in both c++ and lua.

Edit: For windows I’d be glad for some real working code and especially for lua. I can do with boost::filesystem for c++.

Answer 1

For Lua, you want the module Lua Filesystem.

As observed by Nick, accessing the file system itself (as opposed to individual files) is outside the scope of the C and C++ standards. Since Lua itself is (with the exception of the dynamic loader used to implement require() for C modules) written in standard C, the core language lacks many file system features.

However, it is easy to extend the Lua core since (nearly) any platform that has a file system also supports DLLs or shared libraries. Lua File system is a portable library that adds support for directory iteration, file attribute discovery, and the like.

With lfs, emulating some of the capability of DIR in Lua is essentially as simple as:

require 'lfs' dot = arg[1] or '.' for name in lfs.dir(dot) do     local fqn = dot..'/'..name     local attr = lfs.attributes(fqn)     print(name, attr.mode, os.date('%Y-%m-%d %H:%M',attr.modification), attr.size) end 

Which produces output that looks like:

E:...>t-lfs.lua .       directory       2009-04-02 13:23        0 ..      directory       2009-04-02 13:18        0 foo.txt file    2009-02-23 01:56        0 t-lfs.lua       file    2009-04-02 13:18        241  E:...> 

If your copy of Lua came from Lua for Windows, then you already have lfs installed, and the above sample will work out of the box.

Edit: Incidentally, the Lua solution might also be a sensible C or C++ solution. The Lua core is not at all large, provides a dynamic, garbage-collected language, and is easy to interact with from C either as a hosting application or as an extension module. To use lfs from a C application, you would link with the Lua DLL, initialize a Lua state, and get the state to execute the require'lfs' either via luaL_dostring() or by using the C API to retrieve the require() function from the global table, push the string 'lfs', and call the Lua function with something like lua_pcall(L,1,1,0), which leaves the lfs table on the top of the Lua stack.

This approach probably makes the most sense if you already had a need for an embedded scripting language, and Lua meets your requirements.