A fork gives you a brand new process, which is a copy of the current process, with the same code segments. As the memory image changes (typically this is due to different behavior of the two processes) you get a separation of the memory images (Copy On Write), however the executable code remains the same. … Read more
I don’t think that what you are trying to accomplish it’s possible, because in Linux (actually i think it’s UX specific), a process exit code is an 8-bit number: 0-255 (and as a convention, 0 means success, anything else means error) and lots of stuff rely on this fact (including the macros you used). Take … Read more
The code will probably print “ciao” twice as standard output is buffered IO so the internal buffer for standard output will be replicated in the child process and both buffers flushed when each process, the parent and child, exits. It is unrelated to optimization.
unistd.h and fork are part of the POSIX standard. They aren’t available on windows (text.exe in your gcc command hints that’s you’re not on *nix). It looks like you’re using gcc as part of MinGW, which does provide the unistd.h header but does not implement functions like fork. Cygwin does provide implementations of functions like … Read more
Look at this. Use: set follow-fork-mode <mode> Set the debugger response to a program call of fork or vfork. A call to fork or vfork creates a new process. The <mode> argument can be: parent: The original process is debugged after a fork. The child process runs unimpeded. This is the default. child: The new … Read more
Yeah you can pull the changes from the original repo into your fork. Add a remote to it ( since origin will be your fork ) and pull. This from GitHub help: First up, add a remote to the original repo. Help here: http://help.github.com/remotes/ Then you can pull in updates to the original repo. Quote … Read more
On Linux, you can use posix_spawn(2) with the POSIX_SPAWN_USEVFORK flag to avoid the overhead of copying page tables when forking from a large process. See Minimizing Memory Usage for Creating Application Subprocesses for a good summary of posix_spawn(2), its advantages and some examples. To take advantage of vfork(2), make sure you #define _GNU_SOURCE before #include … Read more
All right, so now first of all: what is a zombie process? It’s a process that is dead, but its parent was busy doing some other work, hence it could not collect the child’s exit status. In some cases, the child runs for a very long time, the parent cannot wait for that long, and … Read more
It’s important to distinguish between the file descriptor, which is a small integer that the process uses in its read and write calls to identify the file, and the file description, which is a structure in the kernel. The file offset is part of the file description. It lives in the kernel. As an example, … Read more
I am surprised that there is a problem, but it does seem to be a problem on Linux (I tested on Ubuntu 16.04 LTS running in a VMWare Fusion VM on my Mac) — but it was not a problem on my Mac running macOS 10.13.4 (High Sierra), and I wouldn’t expect it to be … Read more