How can I get the list of files in a directory using C or C++?
How can I get the list of files in a directory using C or C++?
Question
How can I determine the list of files in a directory from inside my C or C++ code?
I'm not allowed to execute the ls
command and parse the results from within my program.
Accepted Answer
In small and simple tasks I do not use boost, I use dirent.h which is also available for windows:
DIR *dir;
struct dirent *ent;
if ((dir = opendir ("c:\\src\\")) != NULL) {
/* print all the files and directories within directory */
while ((ent = readdir (dir)) != NULL) {
printf ("%s\n", ent->d_name);
}
closedir (dir);
} else {
/* could not open directory */
perror ("");
return EXIT_FAILURE;
}
It is just a small header file and does most of the simple stuff you need without using a big template-based approach like boost(no offence, I like boost!).
The author of the windows compatibility layer is Toni Ronkko. In Unix, it is a standard header.
UPDATE 2017:
In C++17 there is now an official way to list files of your file system: std::filesystem
. There is an excellent answer from Shreevardhan below with this source code:
#include <string>
#include <iostream>
#include <filesystem>
namespace fs = std::filesystem;
int main()
{
std::string path = "/path/to/directory";
for (const auto & entry : fs::directory_iterator(path))
std::cout << entry.path() << std::endl;
}
Popular Answer
C++17 now has a std::filesystem::directory_iterator
, which can be used as
#include <string>
#include <iostream>
#include <filesystem>
namespace fs = std::filesystem;
int main() {
std::string path = "/path/to/directory";
for (const auto & entry : fs::directory_iterator(path))
std::cout << entry.path() << std::endl;
}
Also, std::filesystem::recursive_directory_iterator
can iterate the subdirectories as well.
Read more… Read less…
Unfortunately the C++ standard does not define a standard way of working with files and folders in this way.
Since there is no cross platform way, the best cross platform way is to use a library such as the boost filesystem module.
Cross platform boost method:
The following function, given a directory path and a file name, recursively searches the directory and its sub-directories for the file name, returning a bool, and if successful, the path to the file that was found.
bool find_file(const path & dir_path, // in this directory, const std::string & file_name, // search for this name, path & path_found) // placing path here if found { if (!exists(dir_path)) return false; directory_iterator end_itr; // default construction yields past-the-end for (directory_iterator itr(dir_path); itr != end_itr; ++itr) { if (is_directory(itr->status())) { if (find_file(itr->path(), file_name, path_found)) return true; } else if (itr->leaf() == file_name) // see below { path_found = itr->path(); return true; } } return false; }
Source from the boost page mentioned above.
For Unix/Linux based systems:
You can use opendir / readdir / closedir.
Sample code which searches a directory for entry ``name'' is:
len = strlen(name); dirp = opendir("."); while ((dp = readdir(dirp)) != NULL) if (dp->d_namlen == len && !strcmp(dp->d_name, name)) { (void)closedir(dirp); return FOUND; } (void)closedir(dirp); return NOT_FOUND;
Source code from the above man pages.
For a windows based systems:
You can use the Win32 API FindFirstFile / FindNextFile / FindClose functions.
The following C++ example shows you a minimal use of FindFirstFile.
#include <windows.h> #include <tchar.h> #include <stdio.h> void _tmain(int argc, TCHAR *argv[]) { WIN32_FIND_DATA FindFileData; HANDLE hFind; if( argc != 2 ) { _tprintf(TEXT("Usage: %s [target_file]\n"), argv[0]); return; } _tprintf (TEXT("Target file is %s\n"), argv[1]); hFind = FindFirstFile(argv[1], &FindFileData); if (hFind == INVALID_HANDLE_VALUE) { printf ("FindFirstFile failed (%d)\n", GetLastError()); return; } else { _tprintf (TEXT("The first file found is %s\n"), FindFileData.cFileName); FindClose(hFind); } }
Source code from the above msdn pages.
One function is enough, you don't need to use any 3rd-party library (for Windows).
#include <Windows.h>
vector<string> get_all_files_names_within_folder(string folder)
{
vector<string> names;
string search_path = folder + "/*.*";
WIN32_FIND_DATA fd;
HANDLE hFind = ::FindFirstFile(search_path.c_str(), &fd);
if(hFind != INVALID_HANDLE_VALUE) {
do {
// read all (real) files in current folder
// , delete '!' read other 2 default folder . and ..
if(! (fd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) ) {
names.push_back(fd.cFileName);
}
}while(::FindNextFile(hFind, &fd));
::FindClose(hFind);
}
return names;
}
PS: as mentioned by @Sebastian, you could change *.*
to *.ext
in order to get only the EXT-files (i.e. of a specific type) in that directory.
For a C only solution, please check this out. It only requires an extra header:
https://github.com/cxong/tinydir
tinydir_dir dir;
tinydir_open(&dir, "/path/to/dir");
while (dir.has_next)
{
tinydir_file file;
tinydir_readfile(&dir, &file);
printf("%s", file.name);
if (file.is_dir)
{
printf("/");
}
printf("\n");
tinydir_next(&dir);
}
tinydir_close(&dir);
Some advantages over other options:
- It's portable - wraps POSIX dirent and Windows FindFirstFile
- It uses
readdir_r
where available, which means it's (usually) threadsafe - Supports Windows UTF-16 via the same
UNICODE
macros - It is C90 so even very ancient compilers can use it
I recommend using glob
with this reusable wrapper. It generates a vector<string>
corresponding to file paths that fit the glob pattern:
#include <glob.h>
#include <vector>
using std::vector;
vector<string> globVector(const string& pattern){
glob_t glob_result;
glob(pattern.c_str(),GLOB_TILDE,NULL,&glob_result);
vector<string> files;
for(unsigned int i=0;i<glob_result.gl_pathc;++i){
files.push_back(string(glob_result.gl_pathv[i]));
}
globfree(&glob_result);
return files;
}
Which can then be called with a normal system wildcard pattern such as:
vector<string> files = globVector("./*");
Here is a very simple code in C++11
using boost::filesystem
library to get file names in a directory (excluding folder names):
#include <string>
#include <iostream>
#include <boost/filesystem.hpp>
using namespace std;
using namespace boost::filesystem;
int main()
{
path p("D:/AnyFolder");
for (auto i = directory_iterator(p); i != directory_iterator(); i++)
{
if (!is_directory(i->path())) //we eliminate directories
{
cout << i->path().filename().string() << endl;
}
else
continue;
}
}
Output is like:
file1.txt
file2.dat