[ksh93-integration-discuss] Shouldksh93/libshelluse|posix_spawn()| instead of |vfork()| ?

[David Korn]

ksh93 needs to call whatever is the fastest method for creating a process.
To do this, ksh93 calls a wrapper function named spawnveg() that is in the
ast library.  This function combines fork/exec plus specifies the process
group to join or whether to create a new group or not.

This function uses the fastest method available.  The iffe (IF Feature Exists)
script, which runs at compile time, compares the performance of vfork()
and posix_spawn() if both exists and  chooses the fastest. 

Since ksh93 doesn't use threads.   I am not aware of any reason
that vfork() would not be reliable.

David Korn
dgk at research.att.com