I am seeing the following warnings in git head from zic.c: zic.c:1505: warning: ignoring return value of ‘fwrite’, declared with attribute warn_unused_result zic.c:1514: warning: ignoring return value of ‘fwrite’, declared with attribute warn_unused_result zic.c:1752: warning: ignoring return value of ‘fwrite’, declared with attribute warn_unused_result zic.c:1753: warning: ignoring return value of ‘fwrite’, declared with attribute warn_unused_result zic.c:1754: warning: ignoring return value of ‘fwrite’, declared with attribute warn_unused_result zic.c:1755: warning: ignoring return value of ‘fwrite’, declared with attribute warn_unused_result zic.c:1756: warning: ignoring return value of ‘fwrite’, declared with attribute warn_unused_result zic.c:1757: warning: ignoring return value of ‘fwrite’, declared with attribute warn_unused_result zic.c:1758: warning: ignoring return value of ‘fwrite’, declared with attribute warn_unused_result zic.c:1759: warning: ignoring return value of ‘fwrite’, declared with attribute warn_unused_result zic.c:1760: warning: ignoring return value of ‘fwrite’, declared with attribute warn_unused_result zic.c:1772: warning: ignoring return value of ‘fwrite’, declared with attribute warn_unused_result zic.c:1785: warning: ignoring return value of ‘fwrite’, declared with attribute warn_unused_result
Here is the first C line that generated the warning message: (void) fwrite((void *) buf, (size_t) sizeof buf, (size_t) 1, fp); Seems casting to void is not enough. Not sure why the error just started appearing for me last week. I don't see any recent gcc updates. This is gcc version 4.4.5-8 on Debian Squeeze. However, the only place I see fwrite() cast to void is in zic.c, and I see this code in pg_upgrade/utils.c: /* * There's nothing much we can do about it if fwrite fails, but some * platforms declare fwrite with warn_unused_result. Do a little * dance with casting to void to shut up the compiler in such cases. */ size_t rc; rc = fwrite(message, strlen(message), 1, log_opts.internal); /* if we are using OVERWRITE_MESSAGE, add newline to log file */ if (strchr(message, '\r') != NULL) rc = fwrite("\n", 1, 1, log_opts.internal); (void) rc; which was added by this commit: commit b98fd52a5516365e4a90d523cfed906eb7b3e67a Author: Tom Lane <t...@sss.pgh.pa.us> Date: Wed Sep 5 14:36:47 2012 -0400 Silence -Wunused-result warning in contrib/pg_upgrade. This is just neatnik-ism, but since we do it for comparable code in elog.c, we may as well do it here. Should we give zic.c the same treatment? -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + It's impossible for everything to be true. + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers