#
#
# Nimrod's Runtime Library
# (c) Copyright 2012 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 LoadLib*(): TLibHandle
## gets the handle from the current executable. Returns nil if the
## library could not be loaded.
proc UnloadLib*(lib: TLibHandle)
## unloads the library `lib`
proc raiseInvalidLibrary*(name: cstring) {.noinline, noreturn.} =
## raises an `EInvalidLibrary` exception.
var e: ref EInvalidLibrary
new(e)
e.msg = "could not find symbol: " & $name
raise e
proc symAddr*(lib: TLibHandle, name: cstring): pointer
## retrieves the address of a procedure/variable from `lib`. Returns nil
## if the symbol could not be found.
proc checkedSymAddr*(lib: TLibHandle, name: cstring): 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: raiseInvalidLibrary(name)
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 LoadLib(): TLibHandle = return dlopen(nil, RTLD_NOW)
proc UnloadLib(lib: TLibHandle) = dlclose(lib)
proc symAddr(lib: TLibHandle, name: cstring): 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 LoadLib(): TLibHandle =
result = cast[TLibHandle](winLoadLibrary(nil))
proc UnloadLib(lib: TLibHandle) = FreeLibrary(cast[THINSTANCE](lib))
proc symAddr(lib: TLibHandle, name: cstring): pointer =
result = GetProcAddress(cast[THINSTANCE](lib), name)
else:
{.error: "no implementation for dynlib".}