Hi, On Mon, 5 Jan 2026 at 08:28, Prafulla Ranadive <[email protected]> wrote: > > Hello, > > I have started exploring Postgresql recently. > I am trying to build Postgresql from source on a windows machine. I am > referring to the page > https://www.postgresql.org/docs/current/install-meson.html#INSTALL-SHORT-MESON > > The ninja command is failing with the error message: > > PS C:\PostgreSQLworkspace\postgres\build> ninja > [142/2102] Generating src/fe_utils/psqlscan with a custom command > FAILED: src/fe_utils/psqlscan.c > "C:\MyPrograms\Meson\meson.exe" "runpython" "../src/tools/pgflex" > "--builddir" "." "--srcdir" ".." "--privatedir" "src/fe_utils/psqlscan.c.p" > "--flex" "C:\MyPrograms\GnuWin32\bin\flex.EXE" "--perl" > "C:\Strawberry\perl\bin\perl.EXE" "-i" "../src/fe_utils/psqlscan.l" "-o" > "src/fe_utils/psqlscan.c" "--no-backup" "--" "-Cfe" "-p" "-p" > C:\MyPrograms\GnuWin32\bin\flex.EXE: can't open > C:\PostgreSQLworkspace\postgres\build\src\fe_utils\psqlscan.c > [146/2102] Generating src/backend/bootstrap/bootscanner with a custom command > FAILED: src/backend/bootstrap/bootscanner.c > "C:\MyPrograms\Meson\meson.exe" "runpython" "../src/tools/pgflex" > "--builddir" "." "--srcdir" ".." "--privatedir" > "src/backend/bootstrap/bootscanner.c.p" "--flex" > "C:\MyPrograms\GnuWin32\bin\flex.EXE" "--perl" > "C:\Strawberry\perl\bin\perl.EXE" "-i" > "../src/backend/bootstrap/bootscanner.l" "-o" > "src/backend/bootstrap/bootscanner.c" > C:\MyPrograms\GnuWin32\bin\flex.EXE: can't open > C:\PostgreSQLworkspace\postgres\build\src\backend\bootstrap\bootscanner.c > [147/2102] Generating src/backend/parser/scan with a custom command > FAILED: src/backend/parser/scan.c > "C:\MyPrograms\Meson\meson.exe" "runpython" "../src/tools/pgflex" > "--builddir" "." "--srcdir" ".." "--privatedir" "src/backend/parser/scan.c.p" > "--flex" "C:\MyPrograms\GnuWin32\bin\flex.EXE" "--perl" > "C:\Strawberry\perl\bin\perl.EXE" "-i" "../src/backend/parser/scan.l" "-o" > "src/backend/parser/scan.c" "--no-backup" "--" "-CF" "-p" "-p" > C:\MyPrograms\GnuWin32\bin\flex.EXE: can't open > C:\PostgreSQLworkspace\postgres\build\src\backend\parser\scan.c > ninja: build stopped: subcommand failed. > PS C:\PostgreSQLworkspace\postgres\build> > > I have enabled full permission on the folder but still no luck. > > Can someone please help me with this? Any troubleshooting pointers would be a > great help!
Could you let me know where you downloaded flex from? I am wondering whether it might be this: https://gnuwin32.sourceforge.net/packages/flex.htm. For our Windows CI, we use flex and bison from this release instead: https://github.com/lexxmark/winflexbison/releases/tag/v2.5.24. If you have a chance, would you mind trying flex and bison from that source to see if it helps? -- Regards, Nazir Bilal Yavuz Microsoft
