Check if process exists given its pid

Question

Given the pid of a Linux process, I want to check, from a C program, if the process is still running.

Answer 1

Use procfs.

#include 
[...]
struct stat sts;
if (stat("/proc/", &sts) == -1 && errno == ENOENT) {
  // process doesn't exist
}

Easily portable to

• Solaris
• IRIX
• Tru64 UNIX
• BSD
• Linux
• IBM AIX
• QNX
• Plan 9 from Bell Labs