How do I make a file self-update (Native C++)
Write a new executable and delete or save a copy of the old one -- you could send a diff over the network and have a third program, the update monitor or whatever, to apply it. It would be just a small script that could be started from the remote app when it realizes an update is available. The updater could rename itself to $UPDATER_OLD_VERSION or whatever, write an updated copy of itself with the appropriate name, and then when the new updater is run you check if there is a file named $UPDATER_OLD_VERSION in the app directory and delete it. All other files could just be updated/overwritten.
This is how I did it recently. There is a brief overlap of the old program running and the new programming running. It makes use of the trick that you can rename the current executable and bring the new file in place before you shut down the old one. This is not 100% fail safe, but the only way this could "brick" your application is if CopyFile fails.
#include <windows.h>#include <iostream>#include <fstream>void UpgradeService::UpgradeSelf() { std::string temp = root + "\\myprogram_tmp.exe"; remove(temp.c_str()); // ignore return code std::string src = upgradeFolder + "\\myprogram.exe"; std::string dst = root + "\\myprogram.exe"; rename(dst.c_str(),temp.c_str()); CopyFile(src.c_str(),dst.c_str(),false); static char buffer[512]; strcpy(buffer,dst.c_str()); /* CreateProcess API initialization */ STARTUPINFO siStartupInfo; PROCESS_INFORMATION piProcessInfo; memset(&siStartupInfo, 0, sizeof(siStartupInfo)); memset(&piProcessInfo, 0, sizeof(piProcessInfo)); siStartupInfo.cb = sizeof(siStartupInfo); ::CreateProcess(buffer, // application name/path NULL, // command line (optional) NULL, // no process attributes (default) NULL, // default security attributes false, CREATE_DEFAULT_ERROR_MODE | CREATE_NEW_CONSOLE, NULL, // default env NULL, // default working dir &siStartupInfo, &piProcessInfo); ::TerminateProcess( GetCurrentProcess(),0); ::ExitProcess(0); // exit this process // this does not return.}