MySQL 9.0.0
Source Code Documentation
nodiscard.h
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23
24#ifndef MYSQL_BINLOG_UTILS_NODISCARD_H
25#define MYSQL_BINLOG_UTILS_NODISCARD_H
26
27/// The function attribute [[NODISCARD]] is a replacement for
28/// [[nodiscard]] to workaround a gcc bug.
29///
30/// This attribute can appear before a function declaration, and makes
31/// it mandatory for the caller to use the return value. Use this on
32/// functions where it is always essential to check if an error
33/// occurred.
34///
35/// It would be better if we could use [[nodiscard]], but gcc has a
36/// bug that makes it ineffective is some cases:
37/// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84476
38/// OTOH, gnu::warn_unused_result is unaffected by the bug.
39/// Once the bug is fixed, and we drop support for compiler versions
40/// that have the bug, we can replace [[NODISCARD]] by [[nodiscard]].
41///
42/// MSVC gives a warning for gnu::warn_unused_result because it does
43/// not recognize it, so we use gnu::warn_unused_result only on gnuc.
44#ifdef __GNUC__
45#define NODISCARD nodiscard, gnu::warn_unused_result
46#else
47#define NODISCARD nodiscard
48#endif
49
50#endif // MYSQL_BINLOG_UTILS_NODISCARD_H