Missing libm linkage causes undefined symbol errors

When building asyncpg the compiled extension modules fail to load at runtime with errors like:

undefined symbol: log10	(./lib/python3.12/site-packages/asyncpg/pgproto/pgproto.cpython-312-aarch64-linux-gnu.so)

This happens because the C extensions use math functions from libm but don't explicitly link against it.

[./lib/python3.12/site-packages/asyncpg/pgproto/pgproto.cpython-312-aarch64-linux-gnu.so]:
    linux-vdso.so.1 (0x0000ffff9e066000)
    libc.so.6 => /lib64/libc.so.6 (0x0000ffff9ddce000)
    /lib/ld-linux-aarch64.so.1 (0x0000ffff9e019000)
undefined symbol: log10	(./lib/python3.12/site-packages/asyncpg/pgproto/pgproto.cpython-312-aarch64-linux-gnu.so)

I'm building from an older commit, but this may be still an issue in newer versions.

Environment

OS: Amazon Linux 2023 (aarch64)
Python: 3.12.7
Compiler: Clang 20git
asyncpg commit: d0797f1

Solution is to explicitly link libm in setup.py:

...
setuptools.extension.Extension(
            "asyncpg.pgproto.pgproto",
            ["asyncpg/pgproto/pgproto.pyx"],
            extra_compile_args=CFLAGS,
            extra_link_args=LDFLAGS),
            libraries=["m"],
...

Add explicit libm linkage to fix undefined symbol errors

Add explicit libm linkage to fix undefined symbol errors (MagicStack#…

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Missing `libm` linkage causes undefined symbol errors #1297

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Missing libm linkage causes undefined symbol errors #1297

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BwL1289 commented on Jan 8, 2026

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Missing `libm` linkage causes undefined symbol errors #1297