MySQL 8.3.0
Source Code Documentation
nodiscard.h
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22
23#ifndef MYSQL_BINLOG_UTILS_NODISCARD_H
24#define MYSQL_BINLOG_UTILS_NODISCARD_H
25
26/// The function attribute [[NODISCARD]] is a replacement for
27/// [[nodiscard]] to workaround a gcc bug.
28///
29/// This attribute can appear before a function declaration, and makes
30/// it mandatory for the caller to use the return value. Use this on
31/// functions where it is always essential to check if an error
32/// occurred.
33///
34/// It would be better if we could use [[nodiscard]], but gcc has a
35/// bug that makes it ineffective is some cases:
36/// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84476
37/// OTOH, gnu::warn_unused_result is unaffected by the bug.
38/// Once the bug is fixed, and we drop support for compiler versions
39/// that have the bug, we can replace [[NODISCARD]] by [[nodiscard]].
40///
41/// MSVC gives a warning for gnu::warn_unused_result because it does
42/// not recognize it, so we use gnu::warn_unused_result only on gnuc.
43#ifdef __GNUC__
44#define NODISCARD nodiscard, gnu::warn_unused_result
45#else
46#define NODISCARD nodiscard
47#endif
48
49#endif // MYSQL_BINLOG_UTILS_NODISCARD_H