A small and modern C++ wrapper for OS file monitoring systems. Currently it uses Win32 ReadDirectoryChangesW for monitoring changes in Windows. OSX is supported via kqueues and directory scans.
filesentry is a modern C++ wrapper for the SimpleFileWatcher library originally built by James Wynn.
- The Linux implementation shall use
inotify.
Use one of the build scripts or project files provided in build/, or generate your own using premake5.
Here is the demo, provided in SimpleDemo.cpp.
#include <filesentry/FileWatcher.h>
#include <iostream>
int main(int argc, char** argv) {
try {
// create the file watcher object
fs::FileWatcher fileWatcher;
// add a directory watch to the system
// this scans the `test/` directory for any changes
fs::WatchID watchID = fileWatcher.addWatch("test", [](
fs::WatchID watchID, const std::string& dir, const std::string filename, fs::Action action
) -> void {
std::cout << "DIR ( " << dir << " ) FILE ( " << filename << " ) has event " << action << std::endl;
});
std::cout << "Press ^C to exit demo" << std::endl;
// loop until a key is pressed
while( true ) {
fileWatcher.update();
}
}
catch( std::exception& e ) {
fprintf(stderr, "An exception has occurred: %s\n", e.what());
}
return 0;
}A separate project is provided for the demo in the build script.
When some programs write data in Win32, they will generate both an Add and Modify event. This is likely because the program is actually using two separate calls to write its data.
Because of the time it takes to write the data to the file, it may be necessary in some cases to wait a few milliseconds after the event to be able to safely access the file's contents.