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AddResidentP
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1988-02-22
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AddResidentPrg(33.4) ARP Prog Manual AddResidentPrg(33.4)
NAME
AddResidentPrg -- Add a program to the resident list.
SYNOPSIS
node = AddResidentPrg(segment, name)
d0 d1 a0
FUNCTION
ARP's Resident Program manager is a sort of software MMU
that attempts to allow programs to run multiple times with
only one copy of their code in memory. The result is similar
to Unix(tm) shared text processes. Provisions have been
made to allocate extra data segments for programs that are
not reentrant, these are allocated automatically if the
program begins with a ResidentProgramTag and is also on the
resident list. Additionally, the ResidentProgramTag stores
a max stacksize needed to run the program, this is used and
overrides all user stack requests whether or not the program
is on the Resident list.
A program does not need to have a ResidentProgramTag to be
installed on the resident list. Programs are checksummed
upon being added, and checked each time they are obtained.
While not perfect, this provides a reasonable method of
weeding out most non-resident programs. As a general guide,
all ARP programs currently will run as resident programs.
Most current C programs modify their data, and so cannot be
run without using the ResidentProgramTag to allocate and
copy data. Programs which write into their own code
segments, such as those which do SegList splits, will never
run as Resident, and will likely never run under a hardware
MMU either. Some programs, such as MicroSmith's TxED, check
to see if they are on the ResidentList before doing a
seglist split. These should be ok as resident.
All names on the resident list are stored using their
BaseName's only. Matches will succeed if you specify a full
pathname, but the match only examines the basename of each.
This list is protected using a signal semaphore in ArpBase,
so the overall impact on the system for searches is very
low. Generally, you will not need to obtain this semaphore
for yourself, since all these functions (except
CheckSumPrg()) handle the locking of the list for you. In
general, these functions do not need to be called, you
should usually use the higher level LoadPrg() UnLoadPrg()
functions instead.
INPUTS
segment - BPTR as returned by LoadSeg().
name - pointer to a null terminated pathname. This may be
Page 1 (printed 2/22/88)
AddResidentPrg(33.4) ARP Prog Manual AddResidentPrg(33.4)
any valid AmigaDOS pathname, but only the BaseName
of the path is compared and stored. Note that the
resident name does not need to be the same as the
original diskfile name.
RESULT
node - If found, a pointer to the resident program node for
the program. If NULL, it could not be added. Note
that it is impossible to add the same name twice to
the resident list. On failure, more information is
available by calling IoErr().
BUGS
None known
SEE ALSO
ObtainResidentPrg(), RemResidentPrg(), LoadPrg(),
UnLoadPrg(), CheckSumPrg(), ReleaseResidentPrg(),
BaseName().
AUTHOR
SDB
Page 2 (printed 2/22/88)