What is the best way to get PID of all processes in C?

Question

I know, we can get the PIDs of all the running processes using,

ps ax | awk '{print $1}'

I want to know 2 things,
1. Is it a best way? (If not then what is the best way to get it?)
2. Will it work on all the distribution of Linux? (Ex. Ubuntu, RHEL, SLES, etc etc)

Comments

I minor correction in your question. print $2 will show the process id. print $1 will show list of UID (user id) not the PID (process id).

Answer 1

Not sure about your requirement but in linux we have two commands pidof and pidstat. pidof is used to get the details of a specific process and pidstat can list the statistics of all process including pid.

Let me know if looking something different..

Comments

I want PID of all processes and then i have to perform some task using it,

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Yes thats true, pidstat will give you 4-5 parameters and you need to pick only 1 that is PID. Not sure if there is some option to do that in the pidstat (check man page)

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Ok Thank you Sir,
1 more things,
Output of PIDSTAT will be same for all distribution of linux?

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I think so, but not tested...

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Ok Thank you sir,
One more question i wanted to ask,
In Linux, Under '/proc/' all PIDs will be of all Kernel Processes and User Processes, Right?
Is there any way to Distinguish them?

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Ask a fresh query so that it would be helpful to other people in future.

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Sure Sir,
Thank you