nodiscard.h

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/* Copyright (c) 2023, 2024, Oracle and/or its affiliates.
 
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#ifndef MYSQL_UTILS_NODISCARD_H
#define MYSQL_UTILS_NODISCARD_H
 
/// The function attribute [[NODISCARD]] is a replacement for
/// [[nodiscard]] to workaround a gcc bug.
///
/// This attribute can appear before a function declaration, and makes
/// it mandatory for the caller to use the return value.  Use this on
/// functions where it is always essential to check if an error
/// occurred.
///
/// It would be better if we could use [[nodiscard]], but gcc has a
/// bug that makes it ineffective is some cases:
/// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84476
/// OTOH, gnu::warn_unused_result is unaffected by the bug.
/// Once the bug is fixed, and we drop support for compiler versions
/// that have the bug, we can replace [[NODISCARD]] by [[nodiscard]].
///
/// MSVC gives a warning for gnu::warn_unused_result because it does
/// not recognize it, so we use gnu::warn_unused_result only on gnuc.
#ifdef __GNUC__
#define NODISCARD nodiscard, gnu::warn_unused_result
#else
#define NODISCARD nodiscard
#endif
 
#endif  // MYSQL_UTILS_NODISCARD_H