I'm following the example at: http://www.boost.org/doc/libs/1_35_0/doc/html/interprocess/synchronization_m... for locking and writing to a file, but when a flush is called either implicitly due to a full buffer, or an explicit flush no data is written and the fstream bad() call returns true. If I write a small enough amount of data and don't explicitly flush it works because I unlock the file then call close (where an implicit flush occurs). However, if a flush occurs at any time the file lock is locked no data is written and bad() return true. [START OF CODE] #include <fstream> #include <iostream> #include <boost/interprocess/sync/file_lock.hpp> #include <boost/interprocess/sync/scoped_lock.hpp> int main() { std::string tocFile("C:\\temp\\myfile.bin"); std::fstream file; file.open(tocFile.c_str(), std::ios::out | std::ios::binary | std::ios::trunc); if (!file.is_open() || file.bad()) { std::cout << "Open failed" << std::endl; exit(-1); } boost::interprocess::file_lock f_lock(tocFile.c_str()); { boost::interprocess::scoped_lock<boost::interprocess::file_lock> e_lock(f_lock); file.write(tocFile.c_str(),tocFile.length()); if (!file.is_open() || file.bad()) { std::cout << "Write failed" << std::endl; exit(-1); } file.flush(); if (!file.is_open() || file.bad()) { std::cout << "Flush failed" << std::endl; exit(-1); } } file.close(); return 0; } [END OF CODE] -- View this message in context: http://old.nabble.com/Boost-File-Locks-Do-not-work-as-advertised--tp27570072... Sent from the Boost - Users mailing list archive at Nabble.com.