Am 27.08.2010 11:22, schrieb Michael Schnell:
On 08/26/2010 08:52 PM, Alexander Grau wrote:
To make Free Pascal's threading system to work properly, each newly
created FPC thread needs to be initialized (more exactly, the thread
local storage per thread needs to be initialized so threadvars and
heap are working). That is fully automatically done for you if you use
BeginThread (or indirectly by using the TThread class). However, if
you use threads that were created without BeginThread (i.e. external
threads), additional work (currently) might be required. External
threads also include those that were created in external C libraries
(.DLL/.so).
FPC uses it's own way to create threadvars that is OS-specific and not
identical with what other compilers (i.e. Microsoft C and GNU C) do.
While I do think that it would be a good idea to have the FPC RTL follow
theses paradigms (i.e. look at the GNU docs and reverse engineer what M$
C does: we already investigate that; see the appropriate thread(s) in
the FPC developers forum), I in fact don't see why this would get in the
way with external procedures that independently use their own threadvars.
Of course when using heap managed variables (such as Pascal Strings) in
both the main and external functions, a common heap management is
needed, which maybe uses threadvars.
It's not about using the same threadvar system or the same heap
management in FPC binary and non-FPC library. It's about initialising
the FPC-internal systems PER THREAD so that you can USE theadvars, I/O,
exceptions and such in callbacks that are coming back from the library.
Regards,
Sven
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