4 files changed, 49 insertions, 21 deletions

diff --git a/spec/04-term_spec.lua b/spec/04-term_spec.lua
index c5b91e6..50fba45 100644
--- a/spec/04-term_spec.lua
+++ b/spec/04-term_spec.lua
@@ -246,7 +246,7 @@ describe("Terminal:", function()
       flags.iflag = 0
       assert.has.error(function()
         system.tcsetattr(io.stdin, system.TCSANOW, flags)
-      end, "bad argument #3 to 'tcsetattr' (table expected, got number)")
+      end, "bad argument #3, field 'iflag' must be a bitflag object")
     end)
 
 
@@ -255,7 +255,7 @@ describe("Terminal:", function()
       flags.oflag = 0
       assert.has.error(function()
         system.tcsetattr(io.stdin, system.TCSANOW, flags)
-      end, "bad argument #3 to 'tcsetattr' (table expected, got number)")
+      end, "bad argument #3, field 'oflag' must be a bitflag object")
     end)
 
 
@@ -264,7 +264,7 @@ describe("Terminal:", function()
       flags.lflag = 0
       assert.has.error(function()
         system.tcsetattr(io.stdin, system.TCSANOW, flags)
-      end, "bad argument #3 to 'tcsetattr' (table expected, got number)")
+      end, "bad argument #3, field 'lflag' must be a bitflag object")
     end)
 
   end)
diff --git a/src/bitflags.c b/src/bitflags.c
index 39f8af0..e397918 100644
--- a/src/bitflags.c
+++ b/src/bitflags.c
@@ -46,6 +46,32 @@ LSBF_BITFLAG lsbf_checkbitflags(lua_State *L, int index) {
     return obj->flags;
 }
 
+// Validates that the given index is a table containing a field 'fieldname'
+// which is a bitflag object and returns its value.
+// If the index is not a table or the field is not a bitflag object, a Lua
+// error is raised. If the bitflag is not present, the default value is returned.
+// The stack remains unchanged.
+LSBF_BITFLAG lsbf_checkbitflagsfield(lua_State *L, int index, const char *fieldname, LSBF_BITFLAG default_value) {
+    luaL_checktype(L, index, LUA_TTABLE);
+    lua_getfield(L, index, fieldname);
+
+    // if null, return default value
+    if (lua_isnil(L, -1)) {
+        lua_pop(L, 1);
+        return default_value;
+    }
+
+    // check to bitflags
+    LS_BitFlags *obj = luaL_testudata(L, -1, BITFLAGS_MT_NAME);
+    if (obj == NULL) {
+        lua_pop(L, 1);
+        return luaL_error(L, "bad argument #%d, field '%s' must be a bitflag object", index, fieldname);
+    }
+    LSBF_BITFLAG value = obj->flags;
+    lua_pop(L, 1);
+    return value;
+}
+
 /***
 Creates a new bitflag object from the given value.
 @function system.bitflag
diff --git a/src/bitflags.h b/src/bitflags.h
index 0e47246..f16b041 100644
--- a/src/bitflags.h
+++ b/src/bitflags.h
@@ -14,6 +14,15 @@
 // The value will be left on the stack.
 LSBF_BITFLAG lsbf_checkbitflags(lua_State *L, int index);
 
+
+// Validates that the given index is a table containing a field 'fieldname'
+// which is a bitflag object and returns its value.
+// If the index is not a table or the field is not a bitflag object, a Lua
+// error is raised. If the bitflag is not present, the default value is returned.
+// The stack remains unchanged.
+LSBF_BITFLAG lsbf_checkbitflagsfield(lua_State *L, int index, const char *fieldname, LSBF_BITFLAG default_value);
+
+
 // Pushes a new bitflag object with the given value onto the stack.
 // Might raise a Lua error if memory allocation fails.
 void lsbf_pushbitflags(lua_State *L, LSBF_BITFLAG value);
diff --git a/src/term.c b/src/term.c
index 2b44b12..c0699f9 100644
--- a/src/term.c
+++ b/src/term.c
@@ -556,28 +556,13 @@ static int lst_tcsetattr(lua_State *L)
     int r, i;
     int fd = get_console_handle(L);     // first is the console handle
     int act = luaL_checkinteger(L, 2);  // second is the action to take
-    luaL_checktype(L, 3, LUA_TTABLE);   // third is the termios table with fields
 
     r = tcgetattr(fd, &t);
     if (r == -1) return pusherror(L, NULL);
 
-    lua_getfield(L, 3, "iflag");
-    if (!lua_isnil(L, -1)) {
-        t.c_iflag = lsbf_checkbitflags(L, -1);
-    }
-    lua_pop(L, 1);
-
-    lua_getfield(L, 3, "oflag");
-    if (!lua_isnil(L, -1)) {
-        t.c_oflag = lsbf_checkbitflags(L, -1);
-    }
-    lua_pop(L, 1);
-
-    lua_getfield(L, 3, "lflag");
-    if (!lua_isnil(L, -1)) {
-        t.c_lflag = lsbf_checkbitflags(L, -1);
-    }
-    lua_pop(L, 1);
+    t.c_iflag = lsbf_checkbitflagsfield(L, 3, "iflag", t.c_iflag);
+    t.c_oflag = lsbf_checkbitflagsfield(L, 3, "oflag", t.c_oflag);
+    t.c_lflag = lsbf_checkbitflagsfield(L, 3, "lflag", t.c_lflag);
 
     // Skipping the others for now
 
@@ -596,6 +581,14 @@ static int lst_tcsetattr(lua_State *L)
 
     r = tcsetattr(fd, act, &t);
     if (r == -1) return pusherror(L, NULL);
+
+#else
+    // Windows does not have a tcsetattr function, but we check arguments anyway
+    get_console_handle(L, 1); // to validate args
+    luaL_checkinteger(L, 2);
+    lsbf_checkbitflagsfield(L, 3, "iflag", t.c_iflag);
+    lsbf_checkbitflagsfield(L, 3, "oflag", t.c_iflag);
+    lsbf_checkbitflagsfield(L, 3, "lflag", t.c_iflag);
 #endif
 
     lua_pushboolean(L, 1);