------------------------------------------------------------------------------ -- -- -- FLORIST (FSU Implementation of POSIX.5) COMPONENTS -- -- -- -- P O S I X . S E M A P H O R E S -- -- -- -- S p e c -- -- -- -- -- -- This file is a component of FLORIST, an implementation of the POSIX -- -- Ada bindings for use with the GNAT Ada compiler and the FSU Gnu Ada -- -- Runtime Library (GNARL). -- -- -- -- This package specification contains some text extracted from IEEE STD -- -- 1003.5: 1990, Information Technology -- POSIX Ada Language Interfaces -- -- Part 1: Binding for System Application Program Interface, as amended -- -- by IEEE STD 1003.5b: 1996, Amendment 1: Realtime Extensions, copyright -- -- 1996 by the Institute of Electrical and Electronics Engineers, Inc. -- -- -- -- The package specifications in the IEEE standards cited above represent -- -- only a portion of the documents and are not to be interpreteted -- -- outside the context of the documents. The standards must be used in -- -- conjunction with the package specifications in order to claim -- -- conformance. The IEEE takes no responsibility for and will assume no -- -- liability for damages resulting from the reader's misinterpretation of -- -- said information resulting from its out-of-context nature. To order -- -- copies of the IEEE standards, please contact the IEEE Service Center -- -- at 445 Hoes Lane, PO Box 1331, Piscataway, NJ 08855-1331; via phone at -- -- 1-800-678-IEEE, 908-981-1393; or via fax at 908-981-9667. -- -- -- -- These package specifications are distributed in the hope that they -- -- will be useful, but WITHOUT ANY WARRANTY; without even the implied -- -- warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. -- -- -- ------------------------------------------------------------------------------ -- [$Revision: 1.1] with POSIX.C, POSIX.IO, POSIX.Permissions; package POSIX.Semaphores is type Semaphore is limited private; type Semaphore_Descriptor is private; procedure Initialize (Sem : in out Semaphore; Value : in Natural; Is_Shared : in Boolean := False); function Descriptor_Of (Sem : Semaphore) return Semaphore_Descriptor; procedure Finalize (Sem : in out Semaphore); function Open (Name : POSIX.POSIX_String; Masked_Signals : POSIX.Signal_Masking := POSIX.RTS_Signals) return Semaphore_Descriptor; function Open_Or_Create (Name : POSIX.POSIX_String; Permissions : POSIX.Permissions.Permission_Set; Value : Natural; Options : POSIX.IO.Open_Option_Set := -- POSIX.IO.Empty_Set; POSIX.IO.Open_Option_Set (POSIX.IO.Empty_Set); -- Conversion is only to work around a GNAT3.09 problem. Masked_Signals : POSIX.Signal_Masking := POSIX.RTS_Signals) return Semaphore_Descriptor; procedure Close (Sem : in out Semaphore_Descriptor); procedure Unlink_Semaphore (Name : in POSIX.POSIX_String); procedure Wait (Sem : in Semaphore_Descriptor; Masked_Signals : in POSIX.Signal_Masking := POSIX.RTS_Signals); function Try_Wait (Sem : Semaphore_Descriptor) return Boolean; procedure Post (Sem : in Semaphore_Descriptor); function Get_Value (Sem : Semaphore_Descriptor) return Integer; -- .... Change POSIX.5b? -- The Wait and Try_Wait operations are allowed to be interruptible -- by a signal, according to the C binding. Here, we have no -- Masked_Signals parameter. If the system support POSIX threads, -- we are probably OK, since we will want to keep most signals masked, -- in all threads but the corresponding handler (if any). private -- We rely that type Semaphore will be passed by reference, -- so that we can use 'Address of a parameter (even an "in" parameter) -- to get a pointer to the actual object. -- If there is any danger that it will not be passed by reference, -- we will need to enclose the "sem_t" value as an aliased component of a -- record or even of a tagged type. type Dummy is tagged null record; type Semaphore is record Sem : aliased POSIX.C.sem_t; -- to force by-reference parameter mode: D : Dummy; end record; -- The "access constant" is sometimes a lie, but it allows -- us to emulate the POSIX C-language interface without violating -- Ada rules about pointers to variables vs. pointers to constants. type Semaphore_Descriptor is access constant POSIX.C.sem_t; pragma Convention (C, Semaphore_Descriptor); end POSIX.Semaphores;