boostorg/iostreams — pull request #9 by grynko (2014-11-17 11:49:05+00:00)
Title: if a file does not exist and BOOST_IOS::app specified, file_descriptor should create the file

file_descriptor should handle file open mode according to generally accepted convention and uniformly on all platforms:

if both BOOST_IOS::out and BOOST_IOS::app specified, the class must create the file if it doesn't exist (just as it's done in Windows implementation).