C++ POSIX compliant way of reading a directory listing.

#include <dirent.h>

#include <vector>
#include <string>
using namespace std;

/**
 * Read a directory listing into a vector of strings, filtered by file extension.
 * Throws std::exception on error.
 **/
std::vector<std::string> readDirectory(const std::string &directoryLocation, const std::string &extension)
{
    vector<string> result;
    string lcExtension( strToLower(extension) );
	
    DIR *dir;
    struct dirent *ent;

    if ((dir = opendir(directoryLocation.c_str())) == NULL) {
        throw std::exception("readDirectory() - Unable to open directory.");
    }

    while ((ent = readdir(dir)) != NULL)
    {
        string entry( ent->d_name );
        string lcEntry( strToLower(entry) );
        
        // Check extension matches (case insensitive)
        size_t pos = lcEntry.rfind(lcExtension);
        if (pos!=string::npos && pos==lcEntry.length()-lcExtension.length()) {
              result.push_back( entry );
        }
    }

    if (closedir(dir) != 0) {
    	throw std::exception("readDirectory() - Unable to close directory.");
    }

    return result;
}