I have verified the package from jammy-proposed. Steps taken: Reinstall original socket.h, since I had modified the file by hand: $ sudo apt-get --reinstall install libc6-dev Reading package lists... Done Building dependency tree... Done Reading state information... Done 0 to upgrade, 0 to newly install, 1 reinstalled, 0 to remove and 0 not to upgrade. Need to get 0 B/2,099 kB of archives. After this operation, 0 B of additional disk space will be used. (Reading database ... 82723 files and directories currently installed.) Preparing to unpack .../libc6-dev_2.35-0ubuntu3.1_amd64.deb ... Unpacking libc6-dev:amd64 (2.35-0ubuntu3.1) over (2.35-0ubuntu3.1) ... Setting up libc6-dev:amd64 (2.35-0ubuntu3.1) ... Reproduce the error: Output from proc: Pro*C/C++: Release 21.0.0.0.0 - Production on Wed Jun 7 09:11:56 2023 Version 21.7.0.0.0 Copyright (c) 1982, 2022, Oracle and/or its affiliates. All rights reserved. System default option values taken from: /opt/oracle/instantclient_21_7/precomp/admin/pcscfg.cfg Syntax error at line 184, column 4, file /usr/include/x86_64-linux-gnu/sys/socket.h: Error at line 184, column 4 in file /usr/include/x86_64-linux-gnu/sys/socket.h # defien sendmsg __sendmsg64 ...1 PCC-S-02014, Encountered the symbol "defien" when expecting one of the following : a numeric constant, newline, define, endif, error, if, ifdef, ifndef, include, include_next, line, pragma, _Pragma, undef, an immediate preprocessor command, a C token, The symbol "define," was substituted for "defien" to continue. Install from jammy-proposed: $ sudo apt-get install libc6-dev/jammy-proposed Reading package lists... Done Building dependency tree... Done Reading state information... Done Selected version '2.35-0ubuntu3.2' (Ubuntu:22.04/jammy-proposed [amd64]) for 'libc6-dev' Selected version '2.35-0ubuntu3.2' (Ubuntu:22.04/jammy-proposed [amd64]) for 'libc6' because of 'libc6-dev' Selected version '2.35-0ubuntu3.2' (Ubuntu:22.04/jammy-proposed [amd64]) for 'libc-dev-bin' because of 'libc6-dev' The following additional packages will be installed: libc-dev-bin libc6 Suggested packages: glibc-doc Recommended packages: libnss-nis libnss-nisplus The following packages will be upgraded: libc-dev-bin libc6 libc6-dev 3 to upgrade, 0 to newly install, 0 to remove and 0 not to upgrade. Need to get 5,356 kB of archives. After this operation, 0 B of additional disk space will be used. Do you want to continue? [Y/n] Get:1 http://archive.ubuntu.com/ubuntu jammy-proposed/main amd64 libc6-dev amd64 2.35-0ubuntu3.2 [2,100 kB] Get:2 http://archive.ubuntu.com/ubuntu jammy-proposed/main amd64 libc-dev-bin amd64 2.35-0ubuntu3.2 [20.3 kB] Get:3 http://archive.ubuntu.com/ubuntu jammy-proposed/main amd64 libc6 amd64 2.35-0ubuntu3.2 [3,235 kB] Fetched 5,356 kB in 1s (6,727 kB/s) Preconfiguring packages ... (Reading database ... 82723 files and directories currently installed.) Preparing to unpack .../libc6-dev_2.35-0ubuntu3.2_amd64.deb ... Unpacking libc6-dev:amd64 (2.35-0ubuntu3.2) over (2.35-0ubuntu3.1) ... Preparing to unpack .../libc-dev-bin_2.35-0ubuntu3.2_amd64.deb ... Unpacking libc-dev-bin (2.35-0ubuntu3.2) over (2.35-0ubuntu3.1) ... Preparing to unpack .../libc6_2.35-0ubuntu3.2_amd64.deb ... Unpacking libc6:amd64 (2.35-0ubuntu3.2) over (2.35-0ubuntu3.1) ... Setting up libc6:amd64 (2.35-0ubuntu3.2) ... Setting up libc-dev-bin (2.35-0ubuntu3.2) ... Setting up libc6-dev:amd64 (2.35-0ubuntu3.2) ... Processing triggers for man-db (2.10.2-1) ... Processing triggers for libc-bin (2.35-0ubuntu3.1) ... Verification: Output from proc: Pro*C/C++: Release 21.0.0.0.0 - Production on Thu Jun 8 08:55:33 2023 Version 21.7.0.0.0 Copyright (c) 1982, 2022, Oracle and/or its affiliates. All rights reserved. System default option values taken from: /opt/oracle/instantclient_21_7/precomp/admin/pcscfg.cfg