WT-2820 add gcc warn_unused_result attribute (#2938)

* Add the gcc "cold" attribute to the verbose, message, and assorted error functions (informs the compiler that the function is unlikely to be executed).

* Add the WT_IGNORE_RET() macro that ignores return values in the handfull of places we want to ignore return values.

* Replace calls to fprintf() in the utility with calls to util_err(), replace local variable names in error messages with class names.

1 files changed, 12 insertions, 4 deletions

diff --git a/src/support/err.c b/src/support/err.c
index 60fc53cecd0..0be428602bc 100644
--- a/src/support/err.c
+++ b/src/support/err.c
@@ -314,6 +314,7 @@ __wt_eventv(WT_SESSION_IMPL *session, bool msg_event, int error,
  */
 void
 __wt_err(WT_SESSION_IMPL *session, int error, const char *fmt, ...)
+    WT_GCC_FUNC_ATTRIBUTE((cold))
     WT_GCC_FUNC_ATTRIBUTE((format (printf, 3, 4)))
 {
 	va_list ap;
@@ -323,7 +324,7 @@ __wt_err(WT_SESSION_IMPL *session, int error, const char *fmt, ...)
 	 * an error value to return.
 	 */
 	va_start(ap, fmt);
-	(void)__wt_eventv(session, false, error, NULL, 0, fmt, ap);
+	WT_IGNORE_RET(__wt_eventv(session, false, error, NULL, 0, fmt, ap));
 	va_end(ap);
 }
 
@@ -333,6 +334,7 @@ __wt_err(WT_SESSION_IMPL *session, int error, const char *fmt, ...)
  */
 void
 __wt_errx(WT_SESSION_IMPL *session, const char *fmt, ...)
+    WT_GCC_FUNC_ATTRIBUTE((cold))
     WT_GCC_FUNC_ATTRIBUTE((format (printf, 2, 3)))
 {
 	va_list ap;
@@ -342,7 +344,7 @@ __wt_errx(WT_SESSION_IMPL *session, const char *fmt, ...)
 	 * an error value to return.
 	 */
 	va_start(ap, fmt);
-	(void)__wt_eventv(session, false, 0, NULL, 0, fmt, ap);
+	WT_IGNORE_RET(__wt_eventv(session, false, 0, NULL, 0, fmt, ap));
 	va_end(ap);
 }
 
@@ -398,6 +400,7 @@ info_msg(WT_SESSION_IMPL *session, const char *fmt, va_list ap)
  */
 int
 __wt_msg(WT_SESSION_IMPL *session, const char *fmt, ...)
+    WT_GCC_FUNC_ATTRIBUTE((cold))
     WT_GCC_FUNC_ATTRIBUTE((format (printf, 2, 3)))
 {
 	WT_DECL_RET;
@@ -474,6 +477,7 @@ __wt_progress(WT_SESSION_IMPL *session, const char *s, uint64_t v)
 void
 __wt_assert(WT_SESSION_IMPL *session,
     int error, const char *file_name, int line_number, const char *fmt, ...)
+    WT_GCC_FUNC_ATTRIBUTE((cold))
     WT_GCC_FUNC_ATTRIBUTE((format (printf, 5, 6)))
 #ifdef HAVE_DIAGNOSTIC
     WT_GCC_FUNC_ATTRIBUTE((noreturn))
@@ -482,8 +486,8 @@ __wt_assert(WT_SESSION_IMPL *session,
 	va_list ap;
 
 	va_start(ap, fmt);
-	(void)__wt_eventv(
-	    session, false, error, file_name, line_number, fmt, ap);
+	WT_IGNORE_RET(__wt_eventv(
+	    session, false, error, file_name, line_number, fmt, ap));
 	va_end(ap);
 
 #ifdef HAVE_DIAGNOSTIC
@@ -498,6 +502,7 @@ __wt_assert(WT_SESSION_IMPL *session,
  */
 int
 __wt_panic(WT_SESSION_IMPL *session)
+    WT_GCC_FUNC_ATTRIBUTE((cold))
 {
 	F_SET(S2C(session), WT_CONN_PANIC);
 	__wt_err(session, WT_PANIC, "the process must exit and restart");
@@ -521,6 +526,7 @@ __wt_panic(WT_SESSION_IMPL *session)
  */
 int
 __wt_illegal_value(WT_SESSION_IMPL *session, const char *name)
+    WT_GCC_FUNC_ATTRIBUTE((cold))
 {
 	__wt_errx(session, "%s%s%s",
 	    name == NULL ? "" : name, name == NULL ? "" : ": ",
@@ -541,6 +547,7 @@ __wt_illegal_value(WT_SESSION_IMPL *session, const char *name)
  */
 int
 __wt_object_unsupported(WT_SESSION_IMPL *session, const char *uri)
+    WT_GCC_FUNC_ATTRIBUTE((cold))
 {
 	WT_RET_MSG(session, ENOTSUP, "unsupported object operation: %s", uri);
 }
@@ -552,6 +559,7 @@ __wt_object_unsupported(WT_SESSION_IMPL *session, const char *uri)
  */
 int
 __wt_bad_object_type(WT_SESSION_IMPL *session, const char *uri)
+    WT_GCC_FUNC_ATTRIBUTE((cold))
 {
 	if (WT_PREFIX_MATCH(uri, "backup:") ||
 	    WT_PREFIX_MATCH(uri, "colgroup:") ||