Top "Posix" questions

What is SEGV_MAPERR?

What is SEGV_MAPERR, why does it always come up with SIGSEGV?

linux posix segmentation-fault coredump

What does "#define _GNU_SOURCE" imply?

Today I had to use the basename() function, and the man 3 basename (here) gave me some strange message: Notes There …

c posix gnu

What does EAGAIN mean?

As in the title what does EAGAIN mean?

c sockets unix posix

Is there an equivalent to WinAPI's MAX_PATH under linux/unix?

If I want to allocate a char array (in C) that is guaranteed to be large enough to hold any …

c++ c linux unix posix

Unix / Linux: Difference between Real User ID, Effective User ID and Saved User ID

I am already aware of real user id. It is the unique number for a user in the system. In …

linux unix posix

Test for empty string with X""

I know I can test for an empty string in Bash with -z like so: if [[ -z $myvar ]]; then do_…

string bash shell posix

How are the O_SYNC and O_DIRECT flags in open(2) different/alike?

The use and effects of the O_SYNC and O_DIRECT flags is very confusing and appears to vary somewhat …

io posix synchronous

Connecting n commands with pipes in a shell?

I am trying to implement a shell in C. I can execute simple commands just fine with a simple execvp() …

c shell posix pipe

What is the difference between sigaction and signal?

I was about to add an extra signal handler to an app we have here and I noticed that the …

c signals posix

What is the purpose of fork()?

In many programs and man pages of Linux, I have seen code using fork(). Why do we need to use …

c unix posix fork