2012/3/19 Diego Iastrubni <elc...@kde.org> > On יום שני 19 מרץ 2012 12:22:15 Erez D wrote: > > On Mon, Mar 19, 2012 at 12:20 PM, Nadav Har'El > <n...@math.technion.ac.il>wrote: > > > On Mon, Mar 19, 2012, Erez D wrote about "Re: what happens if": > > > > my reason for fork is only for exec() - to protect the first program > > > > from the other. > > > > > > Then you should be all fine. > > Another reason is for interacting with libraries which are "singleton". I > had > to work with a library to talk to some special HW. The library was > designed to > work with one device per process, and I needed to support "many". > > I found myself "forking" and using pipe() to use the API from my main app. > The > problem is that that "fork()" was called from a thread. Read ahead. > > > > If you're talking about the C language, you won't have any of these > > > problems. System calls like close() or dup() do not use any pthread > > > capabilities like mutexes. > > > > > > If you're talking about a different programming language, I frankly > > > have no idea what its fork() does. Maybe you need to write some C > > > code that does fork()/exec() in one function call, and avoid this risk. > > > > i will be using C++. are you sure this is safe ? > > All theory I read before implementing this said this was a bad idea. The > theory says that libc may maintain some mutex inside malloc() which is > called > from printf() for example. This means that even trivial things may kill > your > app. The theory says that in multithreaded applications as soon as you > clone() > (the system called used by pthread_create()) you should execvp. > > In my application (a lot of C++, running on linux 2.6.32, glibc 2.9 and > glibc > 2.11.1 on ARM) erverything worked perfectly against the theory, your > mileage > may vary. > what do you mean by " erverything worked perfectly against the theory" - did it work or did you have problems although you just execvp after clone ?
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