From: Tom Lane <tgl@sss.pgh.pa.us>
To: awatkins1966@gmail.com
cc: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #18995: Building with GCC 14 fails: incompatible pointer
 struct pam_message
In-reply-to: <18995-82058da9ab4337a7@postgresql.org>
References: <18995-82058da9ab4337a7@postgresql.org>
Comments: In-reply-to PG Bug reporting form <noreply@postgresql.org>
	message dated "Wed, 23 Jul 2025 10:00:55 -0000"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <1313565.1753280855.1@sss.pgh.pa.us>
Date: Wed, 23 Jul 2025 10:27:35 -0400
Message-ID: <1313566.1753280855@sss.pgh.pa.us>
Archived-At: 
 <https://www.postgresql.org/message-id/1313566.1753280855%40sss.pgh.pa.us>
Precedence: bulk

PG Bug reporting form <noreply@postgresql.org> writes:
> First, PostgreSQL 17.5 with GCC v13 builds cleaning and runs on Solaris
> 11.4, but building with GCC v14 I get the following:

> gcc -m64 -Wall -Wmissing-prototypes -Wpointer-arith
> -Wdeclaration-after-statement -Werror=vla -Wendif-labels
> -Wmissing-format-attribute -Wimplicit-fallthrough=3 -Wcast-function-type
> -Wshadow=compatible-local -Wformat-security -fno-strict-aliasing -fwrapv
> -fexcess-precision=standard -Wno-format-truncation -Wno-stringop-truncation
> -O2 -I../../../src/include  -D_POSIX_PTHREAD_SEMANTICS
> -I/usr/include/libxml2   -c -o auth.o auth.c
> auth.c:101:9: error: initialization of 'int (*)(int,  struct pam_message **,
> struct pam_response **, void *)' from incompatible pointer type 'int
> (*)(int,  const struct pam_message **, struct pam_response **, void *)'
> [-Wincompatible-pointer-types]
>   101 |         &pam_passwd_conv_proc,
>       |         ^
> auth.c:101:9: note: (near initialization for 'pam_passw_conv.conv')

This doesn't look like a GCC version problem, but like a discrepancy
in the PAM header files, to wit, "const" or not in the expected
signature of pam_passwd_conv_proc.  Can you verify whether or not
pam_appl.h and its subsidiary headers changed?

On my Linux box I find this in /usr/include/security/_pam_types.h:

struct pam_conv {
    int (*conv)(int num_msg, const struct pam_message **msg,
		struct pam_response **resp, void *appdata_ptr);
    void *appdata_ptr;
};

but it seems that "const" is missing in yours.  I guess an alternative
theory is that it was inconsistent all along but you hadn't previously
tried to build --with-pam.

			regards, tom lane