VuNguyen – 09-08 Apr 14

How do get process id using ffi-napi? I'm using this code, which is generated by ChatGPT.

const ffi = require("ffi-napi");
const ref = require("ref-napi");
const iconv = require("iconv-lite");

const user32 = ffi.Library("user32", {
    EnumWindows: ["bool", ["pointer", "int32"]],
    IsWindowVisible: ["bool", ["int32"]],
    GetWindowTextW: ["int", ["int", "pointer", "int"]],
    GetWindowThreadProcessId: ["int32", ["int", "pointer"]],
});

const MAX_TITLE_LENGTH = 255;
const windowInfos = [];

const callback = ffi.Callback("bool", ["int32", "int32"], (hwnd, lParam) => {
    const isVisible = user32.IsWindowVisible(hwnd);
    if (isVisible) {
        const buf = Buffer.alloc(MAX_TITLE_LENGTH * 2); // multiply by 2 for wide char support
        user32.GetWindowTextW(hwnd, buf, buf.length);
        const nullTerminatorIndex = buf.indexOf("\0\0"); // wide char null terminator is two bytes long
        const titleBuffer = buf.slice(0, nullTerminatorIndex);
        const title = iconv.decode(titleBuffer, "utf-16le").trim();

        if (!title) return true;

        try {
            const pid = ref.alloc("int");
            user32.GetWindowThreadProcessId(hwnd, pid);
            const id = pid.deref();
            const windowInfo = {
                id: id,
                title: title,
            };
            windowInfos.push(windowInfo);

            console.log(windowInfo);
        } catch (error) {
            console.error("Error adding window:", error);
        }
    }
    return true;
});

try {
    user32.EnumWindows(callback, 0);
} catch (error) {
    console.error("Error enumerating windows:", error);
}

console.log(windowInfos);

const ffi = require("ffi-napi");
const ref = require("ref-napi");
const iconv = require("iconv-lite");

const user32 = ffi.Library("user32", {
    EnumWindows: ["bool", ["pointer", "int32"]],
    IsWindowVisible: ["bool", ["int32"]],
    GetWindowTextW: ["int", ["int", "pointer", "int"]],
    GetWindowThreadProcessId: ["int32", ["int", "pointer"]],
});

const MAX_TITLE_LENGTH = 255;
const windowInfos = [];

const callback = ffi.Callback("bool", ["int32", "int32"], (hwnd, lParam) => {
    const isVisible = user32.IsWindowVisible(hwnd);
    if (isVisible) {
        const buf = Buffer.alloc(MAX_TITLE_LENGTH * 2); // multiply by 2 for wide char support
        user32.GetWindowTextW(hwnd, buf, buf.length);
        const nullTerminatorIndex = buf.indexOf("\0\0"); // wide char null terminator is two bytes long
        const titleBuffer = buf.slice(0, nullTerminatorIndex);
        const title = iconv.decode(titleBuffer, "utf-16le").trim();

        if (!title) return true;

        try {
            const pid = ref.alloc("int");
            user32.GetWindowThreadProcessId(hwnd, pid);
            const id = pid.deref();
            const windowInfo = {
                id: id,
                title: title,
            };
            windowInfos.push(windowInfo);

            console.log(windowInfo);
        } catch (error) {
            console.error("Error adding window:", error);
        }
    }
    return true;
});

try {
    user32.EnumWindows(callback, 0);
} catch (error) {
    console.error("Error enumerating windows:", error);
}

console.log(windowInfos);

It works, but it just throw the error below randomly after getting some process id. I believe that this error is related to memory allocations.

#
# Fatal error in , line 0
# Check failed: result.second.
#
#
#
#FailureMessage Object: 000000B259F4CD70
 1: 00007FF68D20BD2F v8::internal::CodeObjectRegistry::~CodeObjectRegistry+112159
 2: 00007FF68D12B11F v8::CFunctionInfo::HasOptions+7039
 3: 00007FF68DDFFD72 V8_Fatal+162
 4: 00007FF68D855EBD v8::internal::BackingStore::Reallocate+621
 5: 00007FF68DAC4149 v8::ArrayBuffer::GetBackingStore+137
 6: 00007FF68D1DFDB9 napi_get_typedarray_info+393
 7: 00007FFE9BA18828
 8: 00007FFE9BA17C19
 9: 00007FFE9BA1D003
10: 00007FFE9BA1ED79
11: 00007FFE9BA1DD09
12: 00007FFE9BA1949E
13: 00007FFE9BA180B7
14: 00007FFE9BA1EF63
15: 00007FF68D1DA696 node::Stop+36246
16: 00007FF68DA92F10 v8::internal::Builtins::builtin_handle+320880
17: 00007FF68DA9251F v8::internal::Builtins::builtin_handle+318335
18: 00007FF68DA9280F v8::internal::Builtins::builtin_handle+319087
19: 00007FF68DA92653 v8::internal::Builtins::builtin_handle+318643
... So on

#
# Fatal error in , line 0
# Check failed: result.second.
#
#
#
#FailureMessage Object: 000000B259F4CD70
 1: 00007FF68D20BD2F v8::internal::CodeObjectRegistry::~CodeObjectRegistry+112159
 2: 00007FF68D12B11F v8::CFunctionInfo::HasOptions+7039
 3: 00007FF68DDFFD72 V8_Fatal+162
 4: 00007FF68D855EBD v8::internal::BackingStore::Reallocate+621
 5: 00007FF68DAC4149 v8::ArrayBuffer::GetBackingStore+137
 6: 00007FF68D1DFDB9 napi_get_typedarray_info+393
 7: 00007FFE9BA18828
 8: 00007FFE9BA17C19
 9: 00007FFE9BA1D003
10: 00007FFE9BA1ED79
11: 00007FFE9BA1DD09
12: 00007FFE9BA1949E
13: 00007FFE9BA180B7
14: 00007FFE9BA1EF63
15: 00007FF68D1DA696 node::Stop+36246
16: 00007FF68DA92F10 v8::internal::Builtins::builtin_handle+320880
17: 00007FF68DA9251F v8::internal::Builtins::builtin_handle+318335
18: 00007FF68DA9280F v8::internal::Builtins::builtin_handle+319087
19: 00007FF68DA92653 v8::internal::Builtins::builtin_handle+318643
... So on

5 Replies

Vu NguyenOP•2y ago

These 3 lines of code caused the problem, but I have no idea how to fix it

const pid = ref.alloc("int");
user32.GetWindowThreadProcessId(hwnd, pid);
const id = pid.deref();

const pid = ref.alloc("int");
user32.GetWindowThreadProcessId(hwnd, pid);
const id = pid.deref();

Unknown User•2y ago

Message Not Public

Vu NguyenOP•2y ago

seen few issues like this and there are no solutions on there Okay I just upgraded node to v18 and it worked <:dKN_weird4:1079865640141193276>

Unknown User•2y ago

Message Not Public

reactibot•2y ago

This thread hasn’t had any activity in 36 hours, so it’s now locked. Threads are closed automatically after 36 hours. If you have a followup question, you may want to reply to this thread so other members know they're related. https://discord.com/channels/102860784329052160/565213527673929729/1096361353993793536