How to find the state(blocking or non-blocking) of a particular shell command?

Question

For example,if i use system() command from a c program to invoke a shell command whether it will complete the shell command and then it'll proceed with program or it'll do both concurrently

what are all the various methods available to find this information ?

Answer 1

You can use fork() or exec() for non-blocking, but a system() call is blocking. This means it will wait for your shell command to finish prior to resuming executing of your C program.

Note if you want it to return right away, you can issue your system command with an & behind it and your C program will run concurrently.

Sequential Example: system("long_script.sh");

Concurrent Example: system("long_script.sh &");