[gccsdk] Using Dynamic Areas
John.Tytgat at aaug.net
Sat Jul 19 07:10:52 PDT 2008
In message <d6715ac14f.admin at snowstone.org.uk>
Adam <lists at snowstone.org.uk> wrote:
> On 19 Jul, Lee Noar wrote:
> > Adam wrote:
> > > Hi,
> > >
> > > How do I enable the use of dynamic areas for my app, rather than the
> > > default use of the wimpslot (GCC3.4.6)?
> > You set a system variable with a name based on that of your binary,
> > eg, for gcc you would use:
> > Set gcc$heap ""
> OK, thanks. Does <appname$heap> have to be active at compile time, or
> just run time?
At run time. Just curious: why would you like specifically set it ? We had
an older suggestion to actually change the default (when appname$heap is
not set) based on whether we're running on RISC OS 5 or not (i.e. whether
the WimpSlot size is limited to 28 MByte or not) as this is probably the
biggest reason to explicitly set it.
> Anyway, I guess that means I have to give my binary a name
I don't think so. Suppose you have a !RunImage built which is hardly
unique in its name and being part of real Wimp application, I think you can
actually use your application name and use appname$heap while setting this
too as __program_name string to "appname".
> Looking at the Usage file and the UnixLib header files, I think I need
> to do:
> #include <unixlib/features.h>
#include <features.h>, no ?
> const char * const * const ___program_name = "BayTrader";
Two leading underscores.
> Unfortunately I'm still flumoxed:
> - How many "_"s should there be? The comments seem to say 2, but the
> actual definition uses 3.
The 3 leading underscore variants are internal to UnixLib and is actually
the pointer to the __program_name variable supplied by the user or NULL
when not. This is how WEAK AOF symbols work (and that's different compared
> - My #include line doesn't work. What's the correct way to refer to the
> unixlib headers?
> - I'm completely lost about the series of three "const" declarations
> and the compiler says "initialization from incompatible pointer type".
> Sorry - I'm sure I'm making this more complicated than it should be!
No I don't think so. I think just a little bit more documentation is
needed. I *think* you just need to add:
const char *__program_name = "BayTrader";
John Tytgat, in his comfy chair at home BASS
John.Tytgat at aaug.net ARM powered, RISC OS driven
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