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src\bitvec.c(43): warning C4141: 'dllexport': used more than once

Freshalmost 2 years ago
Mar 14, 20260 views
Confidence Score88%
88%

Problem

I'm installing it on Windows 11 with PostgreSQL 16. I got the git clone to work, but when I ran the nmake command (nmake /F Makefile.win) I'm getting a few errors: src\bitvec.c(43): warning C4141: 'dllexport': used more than once C:\Program Files\PostgreSQL\16\include\server\access/tupmacs.h(65): error C2196: case value '4' already used C:\Program Files\PostgreSQL\16\include\server\access/tupmacs.h(197): error C2196: case value '4' already used src\hnsw.c(190): warning C4141: 'dllexport': used more than once NMAKE : fatal error U1077: 'cl /nologo /I"C:\Program Files\PostgreSQL\16\include\server\port\win32_msvc" /I"C:\Program Files\PostgreSQL\16\include\server\port\win32" /I"C:\Program Files\PostgreSQL\16\include\server" /I"C:\Program Files\PostgreSQL\16\include" /O2 /fp:fast /c src\hnsw.c /Fosrc\hnsw.obj' : return code '0x2' Stop. Can anyone please provide assistance? Thank you. Aaron

Error Output

error C2196: case value '4' already used

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1 Fix

Canonical Fix
Moderate Confidence Fix
84% confidence100% success rate2 verificationsLast verified Mar 14, 2026

Solution: src\bitvec.c(43): warning C4141: 'dllexport': used more than once

Low Risk

It looks like the warning wasn't the issue here (and has been addressed in #598). The error seems to be something with your Postgres installation: [code block] It looks like `sizeof(Datum)` is returning 4, even though that condition should only be added if `SIZEOF_DATUM == 8`. https://github.com/postgres/postgres/blob/REL_16_3/src/include/access/tupmacs.h#L64-L67 (in any case, it doesn't seem

84

Trust Score

2 verifications

100% success
  1. 1

    It looks like the warning wasn't the issue here (and has been addressed in #598)

    It looks like the warning wasn't the issue here (and has been addressed in #598).

  2. 2

    The error seems to be something with your Postgres installation:

    The error seems to be something with your Postgres installation:

  3. 3

    It looks like `sizeof(Datum)` is returning 4, even though that condition should

    It looks like `sizeof(Datum)` is returning 4, even though that condition should only be added if `SIZEOF_DATUM == 8`.

  4. 4

    https://github.com/postgres/postgres/blob/REL_16_3/src/include/access/tupmacs.h#

    https://github.com/postgres/postgres/blob/REL_16_3/src/include/access/tupmacs.h#L64-L67

Validation

Resolved in pgvector/pgvector GitHub issue #593. Community reactions: 1 upvotes.

Verification Summary

Worked: 2
Last verified Mar 14, 2026

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Environment

Submitted by

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Alex Chen

2450 rep

Tags

pgvectorembeddingsvector-search