go:*handler is pointer to interface, not interface

最新推荐文章于 2022-11-29 12:25:45 发布
原创 最新推荐文章于 2022-11-29 12:25:45 发布 · 3k 阅读 · 0 ·
CC 4.0 BY-SA版权
版权声明：本文为博主原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接和本声明。
文章标签：

#go

本文探讨了在特定编程语言中，为何无法声明接口的指针或引用的指针，并通过具体的代码示例进行说明。

摘要生成于 C知道 ，由 DeepSeek-R1 满血版支持， 前往体验 >

一句话总结：不能声明一个接口的指针，如同不能在C++中不能声明一个指向引用的指针。


type handler interface {
	Do()
}
var h *handler //error

C++中不能声明一个指向引用的指针

int&* p; //error

golang错题集
菜刚RyuGou的专栏
07-18 1183
本文即Go语言的那些坑三。 不要对Go并发函数的执行时机做任何假设 请看下列的列子： import ( "fmt" "runtime" "time" ) func main()
golang叠加/重复组合Handler crashed with error runtime error: invalid memory address or nil pointer derefer
webdev_l的博客
01-03 1万+
Handler crashed with error runtime error: invalid memory address or nil pointer dereference 最近新接触golang，用的beego框架；遇到一个挺特别的问题，百度、google都没有这样的情况；程序执行creashed ** Handler crashed with error runtime error:...
Go-Interface
A Flying Bird
09-01 906
Go-Interface
golang拾遗：指针和接口
weixin_45032957的博客
10-12 357
package main import “fmt” func main(){ m := make(map[int]int) m[1] = 1 * 2 m[2] = 2 * 2 fmt.Println(m) m2 := make(map[string]int) m2[“python”] = 1 m2[“golang”] = 2 fmt.Println(m2) } 首先我们来看非interface的引用类型，m和m2明显是两个不同的类型，不过实际上在底层他们是一样的，不信我们用objdump工具检查一下： go
Golang interface 接口详细原理和使用技巧
后端系统和架构
11-29 4546
Golang interface 接口详细原理和使用技巧 审核中
/**************************************************************************** ** ** This file is part of the LibreCAD project, a 2D CAD program ** ** Copyright (C) 2010 R. van Twisk (librecad@rvt.dds.nl) ** Copyright (C) 2001-2003 RibbonSoft. All rights reserved. ** ** ** This file may be distributed and/or modified under the terms of the ** GNU General Public License version 2 as published by the Free Software ** Foundation and appearing in the file gpl-2.0.txt included in the ** packaging of this file. ** ** This program is distributed in the hope that it will be useful, ** but WITHOUT ANY WARRANTY; without even the implied warranty of ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ** GNU General Public License for more details. ** ** You should have received a copy of the GNU General Public License ** along with this program; if not, write to the Free Software ** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA ** ** This copyright notice MUST APPEAR in all copies of the script! ** **********************************************************************/ #ifndef QC_APPLICATIONWINDOW_H #define QC_APPLICATIONWINDOW_H #undef QT_NO_WORKSPACE #include <qworkspace.h> #include "qc_mdiwindow.h" #include "qg_mainwindowinterface.h" #ifdef RS_SCRIPTING #include "qs_scripter.h" #include <qsproject.h> #endif class QG_LibraryWidget; class QG_CadToolBar; class QC_DialogFactory; class QG_LayerWidget; class QG_BlockWidget; class QG_CommandWidget; class QG_CoordinateWidget; class QG_MouseWidget; class QG_SelectionWidget; class QG_RecentFiles; class QG_PenToolBar; class QHelpEngine; class QC_PluginInterface; /** * Main application window. Hold together document, view and controls. * * @author Andrew Mustun */ class QC_ApplicationWindow: public QMainWindow, public QG_MainWindowInterface { Q_OBJECT public: QC_ApplicationWindow(); ~QC_ApplicationWindow(); void initActions(); void initMenuBar(); void initToolBar(); void initStatusBar(); void initSettings(); void restoreDocks(); void storeSettings(); void updateRecentFilesMenu(); void initMDI(); void initView(); bool queryExit(bool force); /** Catch hotkey for giving focus to command line. */ virtual void keyPressEvent(QKeyEvent* e); virtual void keyReleaseEvent(QKeyEvent* e); public slots: virtual void show(); void finishSplashScreen(); void slotFocus(); void slotBack(); void slotKillAllActions(); //void slotNext(); void slotEnter(); void slotFocusCommandLine(); void slotError(const QString& msg); void slotWindowActivated(QWidget* w); void slotWindowsMenuAboutToShow(); void slotWindowsMenuActivated(int); void slotTileHorizontal(); void slotTileVertical(); void slotPenChanged(RS_Pen p); /** generates a new document for a graphic. */ QC_MDIWindow* slotFileNew(RS_Document* doc=NULL); /** opens a document */ void slotFileOpen(); /** * opens a recent file document * @param id File Menu id of the file */ void slotFileOpenRecent(int id); /** * opens the given file. */ void slotFileOpen(const QString& fileName, RS2::FormatType type); /** saves a document */ void slotFileSave(); /** saves a document under a different filename*/ void slotFileSaveAs(); /** auto-save document */ void slotFileAutoSave(); /** exports the document as bitmap */ void slotFileExport(); bool slotFileExport(const QString& name, const QString& format, QSize size, bool black, bool bw=false); /** closes the current file */ void slotFileClose(); /** closing the current file */ void slotFileClosing(); /** prints the current file */ void slotFilePrint(); /** shows print preview of the current file */ void slotFilePrintPreview(bool on); /** exits the application */ void slotFileQuit(); /** toggle the grid */ void slotViewGrid(bool toggle); /** toggle the draft mode */ void slotViewDraft(bool toggle); /** toggle the statusbar */ void slotViewStatusBar(bool toggle); // void slotBlocksEdit(); void slotOptionsGeneral(); void slotScriptOpenIDE(); void slotScriptRun(); void slotRunStartScript(); void slotRunScript(); void slotRunScript(const QString& name); void slotInsertBlock(); void slotInsertBlock(const QString& name); /** shows an about dlg*/ void slotHelpAbout(); void slotHelpManual(); /** dumps entities to file */ void slotTestDumpEntities(RS_EntityContainer* d=NULL); /** dumps undo info to stdout */ void slotTestDumpUndo(); /** updates all inserts */ void slotTestUpdateInserts(); /** draws some random lines */ void slotTestDrawFreehand(); /** inserts a test block */ void slotTestInsertBlock(); /** inserts a test ellipse */ void slotTestInsertEllipse(); /** inserts a test text */ void slotTestInsertText(); /** inserts a test image */ void slotTestInsertImage(); /** unicode table */ void slotTestUnicode(); /** math experimental */ void slotTestMath01(); /** resizes window to 640x480 for screen shots */ void slotTestResize640(); /** resizes window to 640x480 for screen shots */ void slotTestResize800(); /** resizes window to 640x480 for screen shots */ void slotTestResize1024(); signals: void gridChanged(bool on); void draftChanged(bool on); void printPreviewChanged(bool on); void windowsChanged(bool windowsLeft); public: /** * @return Pointer to application window. */ static QC_ApplicationWindow* getAppWindow() { return appWindow; } /** * @return Pointer to workspace. */ QWorkspace* getWorkspace() { return workspace; } /** * @return Pointer to the currently active MDI Window or NULL if no * MDI Window is active. */ QC_MDIWindow* getMDIWindow() { if (workspace!=NULL) { return (QC_MDIWindow*)workspace->activeWindow(); } else { return NULL; } } /** * Implementation from RS_MainWindowInterface (and QS_ScripterHostInterface). * * @return Pointer to the graphic view of the currently active document * window or NULL if no window is available. */ virtual RS_GraphicView* getGraphicView() { QC_MDIWindow* m = getMDIWindow(); if (m!=NULL) { return m->getGraphicView(); } return NULL; } /** * Implementation from RS_MainWindowInterface (and QS_ScripterHostInterface). * * @return Pointer to the graphic document of the currently active document * window or NULL if no window is available. */ virtual RS_Document* getDocument() { QC_MDIWindow* m = getMDIWindow(); if (m!=NULL) { return m->getDocument(); } return NULL; } /** * Creates a new document. Implementation from RS_MainWindowInterface. */ virtual void createNewDocument( const QString& fileName = QString::null, RS_Document* doc=NULL) { slotFileNew(doc); if (fileName!=QString::null && getDocument()!=NULL) { getDocument()->setFilename(fileName); } } /** * Implementation from QG_MainWindowInterface. * * @return Pointer to this. */ virtual QMainWindow* getMainWindow() { return this; } /** * @return Pointer to action handler. Implementation from QG_MainWindowInterface. */ virtual QG_ActionHandler* getActionHandler() { return actionHandler; } //virtual QToolBar* createToolBar(const QString& name); //virtual void addToolBarButton(QToolBar* tb); /** * @return Pointer to the qsa object. */ #ifdef RS_SCRIPTING QSProject* getQSAProject() { if (scripter!=NULL) { return scripter->getQSAProject(); } else { return NULL; } } #endif void redrawAll(); void updateGrids(); /** * Implementation from QG_MainWindowInterface. */ virtual void setFocus2() { setFocus(); } /** Block list widget */ QG_BlockWidget* getBlockWidget(void) { return blockWidget; } protected: void closeEvent(QCloseEvent*); virtual void mouseReleaseEvent(QMouseEvent* e); private: /** Pointer to the application window (this). */ static QC_ApplicationWindow* appWindow; QTimer *autosaveTimer; /** Workspace for MDI */ QWorkspace* workspace; /** Dialog factory */ QC_DialogFactory* dialogFactory; /** Layer list widget */ QG_LayerWidget* layerWidget; /** Block list widget */ QG_BlockWidget* blockWidget; /** Library browser widget */ QG_LibraryWidget* libraryWidget; /** Layer list dock widget */ QDockWidget* layerDockWindow; /** Block list dock widget */ QDockWidget* blockDockWindow; /** Library list dock widget */ QDockWidget* libraryDockWindow; /** Command line */ QG_CommandWidget* commandWidget; QDockWidget* commandDockWindow; /** Coordinate widget */ QG_CoordinateWidget* coordinateWidget; /** Mouse widget */ QG_MouseWidget* mouseWidget; /** Selection Status */ QG_SelectionWidget* selectionWidget; /** Option widget for individual tool options */ QToolBar* optionWidget; /** Recent files list */ QG_RecentFiles* recentFiles; /** Action handler. */ QG_ActionHandler* actionHandler; #ifdef RS_SCRIPTING /** Scripting interface. */ QS_Scripter* scripter; #endif QMenu* fileMenu; QMenu* windowsMenu; QMenu* scriptMenu; QMenu* helpMenu; QMenu* testMenu; /** the main toolbars */ QToolBar* fileToolBar; QToolBar* editToolBar; QToolBar* zoomToolBar; // Toolbar for selecting the current pen QG_PenToolBar* penToolBar; // Toolbar for CAD tools QG_CadToolBar* cadToolBar; QHelpEngine* helpEngine; QDockWidget *helpWindow; QAction* scriptOpenIDE; QAction* scriptRun; QAction* helpAboutApp; QAction* helpManual; QAction *testDumpEntities; QAction *testDumpUndo; QAction *testUpdateInserts; QAction *testDrawFreehand; QAction *testInsertBlock; QAction *testInsertText; QAction *testInsertImage; QAction *testUnicode; QAction *testInsertEllipse; QAction *testMath01; QAction *testResize640; QAction *testResize800; QAction *testResize1024; //Plugin support private: void loadPlugins(); QMenu *findMenu(const QString &searchMenu, const QObjectList thisMenuList, const QString& currentEntry); QList<QC_PluginInterface*> loadedPlugins; public slots: void execPlug(); }; #endif 给出完整的代码注释
07-04
2. **中介者模式**：协调文档、视图、命令间的交互 3. **观察者模式**：通过信号通知状态变化[^2] 4. **资源管理**：统一管理所有子窗口生命周期 5. **命令模式**：封装绘图操作为可执行对象[^1] ### 相关技术问题 ...
Go中的异常处理模式：正确运用panic与error interface的最佳策略（专家分享）
Go语言提供了一套独特的异常处理模型，这与传统的异常处理方法有所不同。在Go中，错误处理是通过显式的错误值来实现的，而不是使用try-catch语句。这种设计强调了程序员应主动处理错误，而不是依赖于异常捕获机制。...
错误 *** Using Compiler 'V5.06 update 5 (build 528)', folder: 'C:\Keil_v5\ARM\ARMCC\Bin' Build target 'LL' compiling main.c... linking... LL\LL.axf: Error: L6218E: Undefined symbol SystemClock_Config (referred from main.o). Not enough information to list image symbols. Not enough information to list load addresses in the image map. Finished: 2 information, 0 warning and 1 error messages. "LL\LL.axf" - 1 Error(s), 0 Warning(s). Target not created. Build Time Elapsed: 00:00:03 main.c文件 /* USER CODE BEGIN Header */ /** ****************************************************************************** * @file : main.c * @brief : Main program body ****************************************************************************** * @attention * * Copyright (c) 2025 STMicroelectronics. * All rights reserved. * * This software is licensed under terms that can be found in the LICENSE file * in the root directory of this software component. * If no LICENSE file comes with this software, it is provided AS-IS. * ****************************************************************************** */ /* USER CODE END Header */ /* Includes ------------------------------------------------------------------*/ #include "main.h" #include "adc.h" #include "dma.h" #include "tim.h" #include "usart.h" #include "gpio.h" /* Private includes ----------------------------------------------------------*/ /* USER CODE BEGIN Includes */ /* USER CODE END Includes */ /* Private typedef -----------------------------------------------------------*/ /* USER CODE BEGIN PTD */ /* USER CODE END PTD */ /* Private define ------------------------------------------------------------*/ /* USER CODE BEGIN PD */ /* USER CODE END PD */ /* Private macro -------------------------------------------------------------*/ /* USER CODE BEGIN PM */ /* USER CODE END PM */ /* Private variables ---------------------------------------------------------*/ /* USER CODE BEGIN PV */ /* USER CODE END PV */ /* Private function prototypes -----------------------------------------------*/ void SystemClock_Config(void); /* USER CODE BEGIN PFP */ /* USER CODE END PFP */ /* Private user code ---------------------------------------------------------*/ /* USER CODE BEGIN 0 */ /* USER CODE END 0 */ /** * @brief The application entry point. * @retval int */ int main(void) { /* USER CODE BEGIN 1 */ /* USER CODE END 1 */ /* MCU Configuration--------------------------------------------------------*/ /* Reset of all peripherals, Initializes the Flash interface and the Systick. */ /* System interrupt init*/ /* SysTick_IRQn interrupt configuration */ NVIC_SetPriority(SysTick_IRQn, NVIC_EncodePriority(NVIC_GetPriorityGrouping(),15, 0)); /** Disable the internal Pull-Up in Dead Battery pins of UCPD peripheral */ /* USER CODE BEGIN Init */ /* USER CODE END Init */ /* Configure the system clock */ SystemClock_Config(); /* USER CODE BEGIN SysInit */ /* USER CODE END SysInit */ /* Initialize all configured peripherals */ MX_GPIO_Init(); MX_DMA_Init(); MX_USART1_UART_Init(); MX_ADC1_Init(); MX_ADC2_Init(); MX_TIM1_Init(); MX_TIM2_Init(); MX_TIM3_Init(); MX_TIM4_Init(); /* USER CODE BEGIN 2 */ /* USER CODE END 2 */ /* Infinite loop */ /* USER CODE BEGIN WHILE */ while (1) { /* USER CODE END WHILE */ /* USER CODE BEGIN 3 */ } /* USER CODE END 3 */ } /** * @brief System Clock Configuration * @retval None */ /* USER CODE BEGIN 4 */ /* USER CODE END 4 */ /** * @brief This function is executed in case of error occurrence. * @retval None */ void Error_Handler(void) { /* USER CODE BEGIN Error_Handler_Debug */ /* User can add his own implementation to report the HAL error return state */ __disable_irq(); while (1) { } /* USER CODE END Error_Handler_Debug */ } #ifdef USE_FULL_ASSERT /** * @brief Reports the name of the source file and the source line number * where the assert_param error has occurred. * @param file: pointer to the source file name * @param line: assert_param error line source number * @retval None */ void assert_failed(uint8_t *file, uint32_t line) { /* USER CODE BEGIN 6 */ /* User can add his own implementation to report the file name and line number, ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */ /* USER CODE END 6 */ } #endif /* USE_FULL_ASSERT */ sys.c文件 /* USER CODE BEGIN Header */ /** ****************************************************************************** * @file : main.c * @brief : Main program body ****************************************************************************** * @attention * * Copyright (c) 2025 STMicroelectronics. * All rights reserved. * * This software is licensed under terms that can be found in the LICENSE file * in the root directory of this software component. * If no LICENSE file comes with this software, it is provided AS-IS. * ****************************************************************************** */ /* USER CODE END Header */ /* Includes ------------------------------------------------------------------*/ #include "main.h" #include "adc.h" #include "dma.h" #include "tim.h" #include "usart.h" #include "gpio.h" /* Private includes ----------------------------------------------------------*/ /* USER CODE BEGIN Includes */ /* USER CODE END Includes */ /* Private typedef -----------------------------------------------------------*/ /* USER CODE BEGIN PTD */ /* USER CODE END PTD */ /* Private define ------------------------------------------------------------*/ /* USER CODE BEGIN PD */ /* USER CODE END PD */ /* Private macro -------------------------------------------------------------*/ /* USER CODE BEGIN PM */ /* USER CODE END PM */ /* Private variables ---------------------------------------------------------*/ /* USER CODE BEGIN PV */ /* USER CODE END PV */ /* Private function prototypes -----------------------------------------------*/ void SystemClock_Config(void); /* USER CODE BEGIN PFP */ /* USER CODE END PFP */ /* Private user code ---------------------------------------------------------*/ /* USER CODE BEGIN 0 */ /* USER CODE END 0 */ /** * @brief The application entry point. * @retval int */ int main(void) { /* USER CODE BEGIN 1 */ /* USER CODE END 1 */ /* MCU Configuration--------------------------------------------------------*/ /* Reset of all peripherals, Initializes the Flash interface and the Systick. */ /* System interrupt init*/ /* SysTick_IRQn interrupt configuration */ NVIC_SetPriority(SysTick_IRQn, NVIC_EncodePriority(NVIC_GetPriorityGrouping(),15, 0)); /** Disable the internal Pull-Up in Dead Battery pins of UCPD peripheral */ /* USER CODE BEGIN Init */ /* USER CODE END Init */ /* Configure the system clock */ SystemClock_Config(); /* USER CODE BEGIN SysInit */ /* USER CODE END SysInit */ /* Initialize all configured peripherals */ MX_GPIO_Init(); MX_DMA_Init(); MX_USART1_UART_Init(); MX_ADC1_Init(); MX_ADC2_Init(); MX_TIM1_Init(); MX_TIM2_Init(); MX_TIM3_Init(); MX_TIM4_Init(); /* USER CODE BEGIN 2 */ /* USER CODE END 2 */ /* Infinite loop */ /* USER CODE BEGIN WHILE */ while (1) { /* USER CODE END WHILE */ /* USER CODE BEGIN 3 */ } /* USER CODE END 3 */ } /** * @brief System Clock Configuration * @retval None */ /* USER CODE BEGIN 4 */ /* USER CODE END 4 */ /** * @brief This function is executed in case of error occurrence. * @retval None */ void Error_Handler(void) { /* USER CODE BEGIN Error_Handler_Debug */ /* User can add his own implementation to report the HAL error return state */ __disable_irq(); while (1) { } /* USER CODE END Error_Handler_Debug */ } #ifdef USE_FULL_ASSERT /** * @brief Reports the name of the source file and the source line number * where the assert_param error has occurred. * @param file: pointer to the source file name * @param line: assert_param error line source number * @retval None */ void assert_failed(uint8_t *file, uint32_t line) { /* USER CODE BEGIN 6 */ /* User can add his own implementation to report the file name and line number, ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */ /* USER CODE END 6 */ } #endif /* USE_FULL_ASS 怎么解决问题
最新发布
08-02
1. **检查函数声明和定义**：首先，确认在某个源文件（如`main.c`或专门的时钟配置文件）中已经定义了`SystemClock_Config`函数。该函数通常用于配置系统时钟，例如设置PLL、系统时钟频率等。 2. **检查函数实现**...
Golang－interface（三 接口类型）
zzbjut
05-12 5120
Go Data Structures: Interfaces Posted on Tuesday, December 1, 2009. Go's interfaces—static, checked at compile time, dynamic when asked for—are, for me, the most exciting part of Go fr
从 Golang中 method has pointer receiverd 异常去理解interface机制
热门推荐
timemachine119的博客
02-08 1万+
从 Golang中 method has pointer receiverd 异常去理解interface机制
go 定义一个结构体并赋初始值_Go中必须谈论的四个迷点
weixin_39972019的博客
01-08 227
很多熟悉Go的程序员们都会说到Go是一门很简单的语言，话虽如此，但实际上Go的简单是基于复杂底层的极简包装。Go在很多地方均做了“隐式”的转换，这也就导致了很多迷惑点，本文总结了Go开发中几个令人迷惑的地方，如有不当之处请指正。nil究竟是什么首先明确一点：nil是值而非类型。nil值只能赋值给slice、map、chan、interface和指针。在Go中，任何类型都会有一个初始值。数值类型的初...
golang的interface传递
keer_zu的博客
04-26 2459
传interface，传递的是一个interface对象，这个对象占用16字节长度，包含一个指向原数据的指针，和一个指向运行时类型信息的指针。 当然对于指向interface的指针这种用法是几乎没有用到的(例子中的Hello4()函数，编译没有成功，我不知道应该怎么写)，也不建议这么用，因为interface本身差不多就是一个指针(其实是两个指针)，stackoverflow有一个问答介绍这个问...
评论
添加红包

请填写红包祝福语或标题

个

红包个数最小为10个

元

红包金额最低5元

当前余额3.43元 前往充值 >
需支付：10.00元
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付元
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明：

1.余额是钱包充值的虚拟货币，按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载，可以购买VIP、付费专栏及课程。

余额充值