GHC.Foreign

Foreign marshalling support for CStrings with configurable encodings

C strings with a configurable encoding

peekCString :: TextEncoding -> CString -> IO String

Marshal a NUL terminated C string into a Haskell string.

peekCStringLen :: TextEncoding -> CStringLen -> IO String

Marshal a C string with explicit length into a Haskell string.

newCString :: TextEncoding -> String -> IO CString

Marshal a Haskell string into a NUL terminated C string.

• the Haskell string may not contain any NUL characters
• new storage is allocated for the C string and must be explicitly freed using free or finalizerFree.

newCStringLen :: TextEncoding -> String -> IO CStringLen

Marshal a Haskell string into a C string (ie, character array) with explicit length information.

• new storage is allocated for the C string and must be explicitly freed using free or finalizerFree.

withCString :: TextEncoding -> String -> (CString -> IO a) -> IO a

Marshal a Haskell string into a NUL terminated C string using temporary storage.

• the Haskell string may not contain any NUL characters
• the memory is freed when the subcomputation terminates (either normally or via an exception), so the pointer to the temporary storage must not be used after this.

withCStringLen :: TextEncoding -> String -> (CStringLen -> IO a) -> IO a

Marshal a Haskell string into a C string (ie, character array) in temporary storage, with explicit length information.

• the memory is freed when the subcomputation terminates (either normally or via an exception), so the pointer to the temporary storage must not be used after this.

withCStringsLen :: TextEncoding -> [String] -> (Int -> Ptr CString -> IO a) -> IO a

Marshal a list of Haskell strings into an array of NUL terminated C strings using temporary storage.

• the Haskell strings may not contain any NUL characters
• the memory is freed when the subcomputation terminates (either normally or via an exception), so the pointer to the temporary storage must not be used after this.

charIsRepresentable :: TextEncoding -> Char -> IO Bool

Determines whether a character can be accurately encoded in a CString.

Pretty much anyone who uses this function is in a state of sin because whether or not a character is encodable will, in general, depend on the context in which it occurs.