Thread: BUG #15280: Clang 6.0.1 compiler warning - strlcpy

The following bug has been logged on the website:

Bug reference:      15280
Logged by:          Steven Winfield
Email address:      steven.winfield@cantabcapital.com
PostgreSQL version: 11beta2
Operating system:   RHEL 7.4
Description:

Hi,

While compiling 11beta2 using clang 6.0.1 this warning crops up quite a lot
in an otherwise quiet build process - so I thought it might be of
interest:

pg_rewind.c:724:4: warning: implicitly declaring library function 'strlcpy'
with type 'unsigned long (char *, const char *, unsigned long)'
[-Wimplicit-function-declaration]
                        strlcpy(full_path, progname, sizeof(full_path));
                        ^
pg_rewind.c:724:4: note: include the header <string.h> or explicitly provide
a declaration for 'strlcpy'
1 warning generated.

In my pg_config.h I have:
#define HAVE_DECL_STRLCPY 1

...and HAVE_STRLCPY is left undefined:
/* #undef HAVE_STRLCPY */

Best wishes,
Steven.

=?utf-8?q?PG_Bug_reporting_form?= <noreply@postgresql.org> writes:
> While compiling 11beta2 using clang 6.0.1 this warning crops up quite a lot
> in an otherwise quiet build process - so I thought it might be of
> interest:
> pg_rewind.c:724:4: warning: implicitly declaring library function 'strlcpy'
> with type 'unsigned long (char *, const char *, unsigned long)'
> [-Wimplicit-function-declaration]

Yeah, this is a known problem caused by autoconf doing its "is this
function declared" test in a way that clang doesn't play nice with.

There's a fix for this upstream:

http://git.savannah.gnu.org/cgit/autoconf.git/commit/?id=82ef7805faffa151e724aa76c245ec590d174580

and we've been patiently waiting for an autoconf release that
incorporates it ...

            regards, tom lane