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pgsql: Work around a subtle portability problem in use of printf %s

From: tgl(at)postgresql(dot)org (Tom Lane)
To: pgsql-committers(at)postgresql(dot)org
Subject: pgsql: Work around a subtle portability problem in use of printf %s
Date: 2010-05-08 16:40:45
Message-ID: 20100508164045.8B72B7541D2@cvs.postgresql.org (view raw or flat)
Thread:
Lists: pgsql-committers
Log Message:
-----------
Work around a subtle portability problem in use of printf %s format.
Depending on which spec you read, field widths and precisions in %s may be
counted either in bytes or characters.  Our code was assuming bytes, which
is wrong at least for glibc's implementation, and in any case libc might
have a different idea of the prevailing encoding than we do.  Hence, for
portable results we must avoid using anything more complex than just "%s"
unless the string to be printed is known to be all-ASCII.

This patch fixes the cases I could find, including the psql formatting
failure reported by Hernan Gonzalez.  In HEAD only, I also added comments
to some places where it appears safe to continue using "%.*s".

Tags:
----
REL8_0_STABLE

Modified Files:
--------------
    pgsql/src/backend/parser:
        scansup.c (r1.29 -> r1.29.4.1)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/scansup.c?r1=1.29&r2=1.29.4.1)
    pgsql/src/backend/utils/error:
        elog.c (r1.155.4.11 -> r1.155.4.12)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/error/elog.c?r1=1.155.4.11&r2=1.155.4.12)
    pgsql/src/interfaces/libpq:
        fe-misc.c (r1.112.4.1 -> r1.112.4.2)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/fe-misc.c?r1=1.112.4.1&r2=1.112.4.2)

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