foreign-data.md

+# Allocating space in the bss and data segment from haskell
+
+
+One is forced to use an external C file to allocate data in the bss or data segment even though no code at all will be output and the object file will simply contain a linker directive to allocate some space. This is a deficiency in the current FFI spec.
+
+## Proposal (experimental in jhc)
+
+
+allow declarations of the form 
+
+```wiki
+foreign space <n> :: Ptr <type>
+```
+
+
+where n is the number of elements to allocate (default 1) and type is a basic type or a renaming thereof. 
+
+
+the space allocated will be n\*sizeof type for the sizeof as specified by the Storable class. user defined types (other than simple newtype or type renaming of built in types) may not be used. 
+
+
+if the type is 'forall a . Ptr a' then the size will be assumed to be one byte.
+
+### initialized data
+
+
+initialized data is trickier, a possible syntax is 
+
+```wiki
+
+foreign space <n> :: Ptr <type> = constant
+
+where constant may be one of 
+
+
+an initialized list [ 0, 1, 2, ...]
+
+a "string" to be interpreted as utf8 or unicode code points depending on what type of pointer it is assigned to.
+
+```
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