1 files changed, 84 insertions, 0 deletions
diff --git a/lib/pure/dynlib.nim b/lib/pure/dynlib.nim
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+++ b/lib/pure/dynlib.nim
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+#
+#
+#            Nimrod's Runtime Library
+#        (c) Copyright 2009 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## This module implements the ability to access symbols from shared
+## libraries. On POSIX this uses the ``dlsym`` mechanism, on 
+## Windows ``LoadLibrary``. 
+
+type
+  TLibHandle* = pointer ## a handle to a dynamically loaded library
+
+proc LoadLib*(path: string): TLibHandle
+  ## loads a library from `path`. Returns nil if the library could not 
+  ## be loaded.
+
+proc UnloadLib*(lib: TLibHandle)
+  ## unloads the library `lib`
+
+proc symAddr*(lib: TLibHandle, name: string): pointer
+  ## retrieves the address of a procedure/variable from `lib`. Returns nil
+  ## if the symbol could not be found.
+
+proc checkedSymAddr*(lib: TLibHandle, name: string): pointer =
+  ## retrieves the address of a procedure/variable from `lib`. Raises
+  ## `EInvalidLibrary` if the symbol could not be found.
+  result = symAddr(lib, name)
+  if result == nil: 
+    var e: ref EInvalidLibrary
+    new(e)
+    e.msg = "could not find symbol: " & name
+    raise e
+
+when defined(posix):
+  #
+  # =========================================================================
+  # This is an implementation based on the dlfcn interface.
+  # The dlfcn interface is available in Linux, SunOS, Solaris, IRIX, FreeBSD,
+  # NetBSD, AIX 4.2, HPUX 11, and probably most other Unix flavors, at least
+  # as an emulation layer on top of native functions.
+  # =========================================================================
+  #
+  var
+    RTLD_NOW {.importc: "RTLD_NOW", header: "<dlfcn.h>".}: int
+
+  proc dlclose(lib: TLibHandle) {.importc, header: "<dlfcn.h>".}
+  proc dlopen(path: CString, mode: int): TLibHandle {.
+      importc, header: "<dlfcn.h>".}
+  proc dlsym(lib: TLibHandle, name: cstring): pointer {.
+      importc, header: "<dlfcn.h>".}
+
+  proc LoadLib(path: string): TLibHandle = return dlopen(path, RTLD_NOW)
+  proc UnloadLib(lib: TLibHandle) = dlclose(lib)
+  proc symAddr(lib: TLibHandle, name: string): pointer = 
+    return dlsym(lib, name)
+
+elif defined(windows) or defined(dos):
+  #
+  # =======================================================================
+  # Native Windows Implementation
+  # =======================================================================
+  #
+  type
+    THINSTANCE {.importc: "HINSTANCE".} = pointer
+
+  proc FreeLibrary(lib: THINSTANCE) {.importc, header: "<windows.h>", stdcall.}
+  proc winLoadLibrary(path: cstring): THINSTANCE {.
+      importc: "LoadLibraryA", header: "<windows.h>", stdcall.}
+  proc GetProcAddress(lib: THINSTANCE, name: cstring): pointer {.
+      importc: "GetProcAddress", header: "<windows.h>", stdcall.}
+
+  proc LoadLib(path: string): TLibHandle =
+    result = cast[TLibHandle](winLoadLibrary(path))
+  proc UnloadLib(lib: TLibHandle) = FreeLibrary(cast[THINSTANCE](lib))
+
+  proc symAddr(lib: TLibHandle, name: string): pointer =
+    result = GetProcAddress(cast[THINSTANCE](lib), name)
+
+else:
+  {.error: "no implementation for dynlib".}