On 16 January 2011 08:50, ali hagigat wrote: > Add support for multithreading using the POSIX threads library. This > option sets flags for both the preprocessor and linker. It does not > affect the thread safety of object code produced by the compiler or > that of libraries supplied with it. > -------------------------------------------------------------- > What is the meaning of thread safety? I wonder if anybody knows what > flags are set and please write a simple example of a multi-thread > code. The flags are platform-specific. For GNU/Linux it passes -D_REENTRANT to the preprocessor and -lpthread to the linker. This list really isn't the place to learn what thread-safety means, or to learn about multithreading in general. There are lots of books and online documentation covering it.