[fpc-devel] fpfork

Michael Schnell mschnell at lumino.de
Mon Feb 11 11:52:49 CET 2008

As I intend to port FP to a non MMU architecture at some point in the 
future I came across this issue:

In the RTL there are some functions that do a fork. The RTL supports as 
well calling fork() as vfork() API (via fpFork and fpVFork).

Here a setting USE_VFORK is acknowledged to decide which one is to be used.

 - not in all instances the difference is provided. sometimes fork() is 
done unconditionally
 - Why is fork used at all. AFAIK, all systems can do vfork() (with 
_at_least_ the same performance as fork() and thus the difference is not 
needed. Regarding the function there is a difference between fork() and 
vfork() only if exec?() is _not_ called immediately afterwards, which 
seems to be the case in the FP RTL.
 - vfork seems to be used in BSD and SUNOS. Why just in these systems ?
 - when doing a non-MMU (µCLinux) architecture fork is not available. 
What is the best way of handling that situation ? (Should we introduce a 
UCLINUX OS flavor ?)


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