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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"ffi: buffer/arraybuffer args reject BigInt pointers in multi-argument fast signatures","articleBody":"### Version\n\nmain\n\n### Platform\n\n```text\nLinux\n```\n\n### Subsystem\n\nffi\n\n### What steps will reproduce the bug?\n\n`repro.c`\n```c\n#include \u003cstdint.h>\n\nuint64_t ptr_one(void *p) { return (uint64_t)(uintptr_t)p; }\nuint64_t ptr_two(void *p, uint64_t extra) { return (uint64_t)(uintptr_t)p + extra; }\n```\n\nCompile it with\n```sh\n$ cc -shared -fPIC -o repro.so repro.c\n```\n\n`repro.js`\n```js\nimport { dlopen } from 'node:ffi';\n\nconst { lib, functions } = dlopen(new URL('repro.so', import.meta.url).pathname, {\n  ptr_one: { arguments: ['buffer'], return: 'u64' },\n  ptr_two: { arguments: ['buffer', 'u64'], return: 'u64' },\n});\n\nfor (const [label, call] of [\n  ['1-arg buffer(10n)    ', () => functions.ptr_one(10n)],\n  ['2-arg buffer(10n, 0n)', () => functions.ptr_two(10n, 0n)],\n]) {\n  try {\n    console.log(label, '->', call());\n  } catch (err) {\n    console.log(label, '-> THREW', err.code, '-', err.message);\n  }\n}\n\nlib.close();\n```\n\n### How often does it reproduce? Is there a required condition?\n\nAlways\n\n### What is the expected behavior? Why is that the expected behavior?\n\n```console\n1-arg buffer(10n)     -> 10n\n2-arg buffer(10n, 0n) -> 10n\n```\n\nExpected both to return `10n`, matching the SB/libffi paths which accept BigInt pointers at every arity; if rejection were intended it should be `ERR_INVALID_ARG_VALUE` with an `Argument N` prefix like the rest of the module.\n\n### What do you see instead?\n\n```console\n1-arg buffer(10n)     -> 10n\n2-arg buffer(10n, 0n) -> THREW ERR_INVALID_ARG_TYPE - The first argument must be a Buffer, ArrayBuffer, or ArrayBufferView\n```\n\nThe one-argument signature returns `10n` while the identical buffer type in a two-argument signature throws `ERR_INVALID_ARG_TYPE`.\n\n### Additional information\n\n_No response_","author":{"url":"https://github.com/trivikr","@type":"Person","name":"trivikr"},"datePublished":"2026-08-02T16:33:30Z","url":"https://github.com/nodejs/node/issues/64963"}