From 6586b015f1211ccd6e3e89b44dcb2116347edf89 Mon Sep 17 00:00:00 2001 From: Jonathan Wakely Date: Wed, 27 Mar 2024 11:07:17 +0000 Subject: [PATCH] libstdc++: Remove noexcept from non-const std::basic_string::data() [PR99942] The C++17 non-const overload of data() allows modifying the string contents directly, so for the COW string we must do a copy-on-write to unshare it. That means allocating, which can throw, so it shouldn't be noexcept. libstdc++-v3/ChangeLog: PR libstdc++/99942 * include/bits/cow_string.h (data()): Change to noexcept(false). --- libstdc++-v3/include/bits/cow_string.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/libstdc++-v3/include/bits/cow_string.h b/libstdc++-v3/include/bits/cow_string.h index 5d81bfc1230..75a2d887ad6 100644 --- a/libstdc++-v3/include/bits/cow_string.h +++ b/libstdc++-v3/include/bits/cow_string.h @@ -2267,9 +2267,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION * * This is a pointer to the character sequence held by the string. * Modifying the characters in the sequence is allowed. + * + * The standard requires this function to be `noexcept` but for the + * Copy-On-Write string implementation it can throw. This function + * allows modifying the string contents directly, which means we + * must copy-on-write to unshare it, which requires allocating memory. */ _CharT* - data() noexcept + data() noexcept(false) { _M_leak(); return _M_data(); -- 2.47.2