system call:exec

[vignesh babu <kbabu_15@yahoo.co.in>]

  I am k.vignesh babu.Iam having doubt regarding a
exec system call(execlp,execle,execv,execvp,execvp).
All the above mentioned system call will create
another copy and execute as separate process.why it is
executing as separate process? and after executing a
exec system call control is not transfered to invoked
procedure why?.Is it possible to execute a process
using system call without creating new process.

                              best regards 


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