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Re: [v1] Add Reiwa era tests to time/tst-strftime3.c
- From: DJ Delorie <dj at redhat dot com>
- To: Steve Ellcey <sellcey at marvell dot com>
- Cc: libc-alpha at sourceware dot org, tamuki at linet dot gr dot jp, digitalfreak at lingonborough dot com
- Date: Wed, 03 Apr 2019 17:55:15 -0400
- Subject: Re: [v1] Add Reiwa era tests to time/tst-strftime3.c
Steve Ellcey <sellcey@marvell.com> writes:
> tst-strftime3.c:443:62: error: ‘%s’ directive output may be truncated writing up to 49 bytes into a region of size between 0 and 30 [-Werror=format-truncation=]
Fixed thusly:
snprintf will only truncate the output if the data its given
is corrupted, but a truncated buffer will not match the
"pristine" data's buffer, which is all we need. So just
disable the warning via the DIAG macros.
2019-04-03 DJ Delorie <dj@redhat.com>
* time/tst-strftime3.c (tm_to_printed): Disable warning about
snprintf truncating output.
diff --git a/time/tst-strftime3.c b/time/tst-strftime3.c
index 32ce0d93e2..eeca0921cb 100644
--- a/time/tst-strftime3.c
+++ b/time/tst-strftime3.c
@@ -25,6 +25,7 @@
#include <support/check.h>
#include <array_length.h>
+#include <libc-diag.h>
/* These exist for the convenience of writing the test data, because
zero-based vs one-based. */
@@ -440,6 +441,14 @@ tm_to_printed (struct tm *tm, char *buffer)
sprintf (temp, "%d", tm->tm_wday);
}
+ DIAG_PUSH_NEEDS_COMMENT;
+#if __GNUC_PREREQ (9, 0)
+ /* GCC 9 warns that strncmp may truncate its output, but that's why
+ we're using it. When it needs to truncate, it got corrupted
+ data, and we only care that the string is different than valid
+ data, which won't truncate. */
+ DIAG_IGNORE_NEEDS_COMMENT (9, "-Wformat-truncation=");
+#endif
snprintf (buffer, TMBUFLEN, "%04d/%02d/%02d %02d:%02d:%02d %s",
tm->tm_year + 1900,
tm->tm_mon + 1,
@@ -448,6 +457,7 @@ tm_to_printed (struct tm *tm, char *buffer)
tm->tm_min,
tm->tm_sec,
wn);
+ DIAG_POP_NEEDS_COMMENT;
}
static int