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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[BUG]: Compiling PTX with undefined extern succeeds and produces empty kernel","articleBody":"### Is this a duplicate?\n\n- [x] I confirmed there appear to be no [duplicate issues](https://github.com/NVIDIA/cuda-python/issues) for this bug and that I agree to the [Code of Conduct](CODE_OF_CONDUCT.md)\n\n### Type of Bug\n\nSilent Failure\n\n### Component\n\ncuda.core\n\n### Describe the bug\n\nAttempting to compile PTX with an undefined extern function seems to succeed and produce a cubin with an empty kernel. I am doing this like:\n\n```python\nfrom cuda.core.experimental import Program, ProgramOptions\n\noptions = ProgramOptions(arch=\"sm_75\")\nprogram = Program(code, code_type=\"ptx\", options=options)\ncubin = program.compile(\"cubin\")\n```\n\nThe same PTX compiled with ptxas results in a failure to compile:\n\n```\n$ ptxas -arch sm_75 add_float16.ptx \nptxas fatal   : Unresolved extern function '_ZplRK6__halfS1__1'\n```\n\nAm I using the `Program.compile()` interface incorrectly?\n\n### How to Reproduce\n\nRun the attached file:\n\n```\npython cudapy.py\n```\n\nThis will produce a cubin with an empty kernel, and show `ptxas` raises an error for the same PTX.\n\n[cudapy.py](https://github.com/user-attachments/files/22028945/cudapy.py)\n\n### Expected behavior\n\nAn exception or some other error raised by `Program.compile()`\n\n### Operating System\n\nUbuntu Linux\n\n### nvidia-smi output\n\n_No response_","author":{"url":"https://github.com/gmarkall","@type":"Person","name":"gmarkall"},"datePublished":"2025-08-28T16:00:43Z","url":"https://github.com/NVIDIA/cuda-python/issues/920"}