On 4/3/2010 6:36 AM, Schwab,Wilhelm K wrote:
Andreas, John, anybody,
I need to find the address of a "function" (it is in fact a global structure pointer somewhere in memory) and pass it to another function.
Suppose the structure is called Type and the function allocate_one(). I call the function something like
allocateOne:type size:anInt <cdecl: SomeOtherStruct* 'allocate_one' ( Type* long )>
but I am having an awful time getting the pointer to Type. Given that dlsym() will return a pointer to it, how can I represent that in Smalltalk? I have tried variations on
"Indirectly call dlsym()" address := Library default getProcAddress:'name_of_global_struct'.
"try to create Type* from the resulting address" type := Type fromHandle:address. type := Type fromHandle:address getHandle. type := ExternalData fromHandle:address type:Type externalType asPointerType.
Something := Library default allocateOne:type size:2.
and it either complains about bad arguments during the call or segment faults. Any ideas or similar examples?
The return type of getProcAddress: is likely wrong. It should be declared to return void* which will cause it to return an ExternalData. With an ExternalData your second variant "Type fromHandle: data getHandle" will work. Cheers, - Andreas