dl: add dynamic load module

vlib/dl/dl_nix.c.v

@@ -0,0 +1,19 @@
+module dl
+
+#include <dlfcn.h>
+
+fn C.dlopen(filename charptr, flags int) voidptr
+fn C.dlsym(handle voidptr, symbol charptr) voidptr
+
+pub const (
+	RTLD_NOW = C.RTLD_NOW
+	DL_EXT = '.so'
+)
+
+pub fn open(filename string, flags int) voidptr {
+	return C.dlopen(filename.str, flags)
+}
+
+pub fn sym(handle voidptr, symbol string) voidptr {
+	return C.dlsym(handle, symbol.str)
+}

vlib/dl/dl_test.v

@@ -0,0 +1,28 @@
+import dl
+
+fn test_dl() {
+	$if linux {
+		run_test_linux()
+		return
+	}
+	$if windows {
+		run_test_windows()
+		return
+	} $else {
+		eprint('currently not implemented on this platform')
+	}
+}
+
+fn run_test_linux() {
+	// ensure a not-existing dl won't be loaded
+	h := dl.open('not-existing-dynamic-link-library', dl.RTLD_NOW)
+	// println('handle = $h')
+	assert h == 0
+}
+
+fn run_test_windows() {
+	// ensure a not-existing dl won't be loaded
+	h := dl.open('not-existing-dynamic-link-library', dl.RTLD_NOW)
+	// println('handle = $h')
+	assert h == 0
+}

vlib/dl/dl_windows.c.v

@@ -0,0 +1,18 @@
+module dl
+
+pub const (
+	RTLD_NOW = 0
+	DL_EXT = '.dll'
+)
+
+fn C.LoadLibraryA(libfilename byteptr) voidptr
+fn C.GetProcAddress(handle voidptr, procname byteptr) voidptr
+
+pub fn open(filename string, flags int) voidptr {
+	res := C.LoadLibraryA(filename.str)
+	return res
+}
+
+pub fn sym(handle voidptr, symbol string) voidptr {
+	return C.GetProcAddress(handle, symbol.str)
+}