From a3f2857ebc0792114a0cf52b62532d73e8d5a338 Mon Sep 17 00:00:00 2001
From: Ulf Hermann <ulf.hermann@qt.io>
Date: Tue, 18 Apr 2023 15:06:23 +0200
Subject: [PATCH] QContainerInfo: Detect presence of reserve()

This is handy if you want to reserve if possible or just fill the
container right away if not.

Task-number: QTBUG-112227
Change-Id: I3d085c1ce2448150bc044c3513572e02161244f4
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
---
 src/corelib/global/qcontainerinfo.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/corelib/global/qcontainerinfo.h b/src/corelib/global/qcontainerinfo.h
index e27877073f..14468510a5 100644
--- a/src/corelib/global/qcontainerinfo.h
+++ b/src/corelib/global/qcontainerinfo.h
@@ -50,6 +50,11 @@ inline constexpr bool has_size_v = false;
 template<typename C>
 inline constexpr bool has_size_v<C, std::void_t<decltype(C().size())>> = true;
 
+template<typename C, typename = void>
+inline constexpr bool has_reserve_v = false;
+template<typename C>
+inline constexpr bool has_reserve_v<C, std::void_t<decltype(C().reserve(0))>> = true;
+
 template<typename C, typename = void>
 inline constexpr bool has_clear_v = false;
 template<typename C>