未定义的引用 - 在C ++中`a = -b;`和`a = -1 * b;`和`a = 0-b'之间应该有区别吗？ [英] Undefined reference - should there be a difference between `a = -b;` and `a = -1*b;` and `a = 0-b` in C++?
本文介绍了未定义的引用 - 在C ++中`a = -b;`和`a = -1 * b;`和`a = 0-b'之间应该有区别吗？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
也许这是在某个地方回答，我只是不知道的话搜索它。我试图理解，如果我看到一个错误，或者如果我不明白减号运算符。我的项目有以下结构，包括生成的文件：
test
├──src
│├──TipCoordinate.cpp
│└──TipCoordinate.hpp
└──UnitTest
├──main.cpp
├──main.o
├──Makefile
├──TipCoordinate.o
├ ──UnitTest.pro
└──UnitTest.pro.user
我在类标题中定义了一个常量，如下所示：
class TipCoordinate {
public：
TipCoordinate（）{};
〜TipCoordinate（）{};
void Z（const float z）;
private：
static const float sREFERENCE_SPHERE_RADIUS = 12;
};
我的类cpp文件中的以下代码将无法编译：
#includeTipCoordinate.hpp
void TipCoordinate :: Z（const float z）{
float z_origin_ = -sREFERENCE_SPHERE_RADIUS;
}
我收到错误 ... / model / TipCoordinate.cpp：143：错误：未定义引用'TipCoordinate :: sREFERENCE_SPHERE_RADIUS'
但是，如果我只是更改它，是非常快乐的：
#includeTipCoordinate.hpp
void TipCoordinate :: Z（const float z）{
float z_origin_ = -1 * sREFERENCE_SPHERE_RADIUS;
}
或者，这也适用于：
#includeTipCoordinate.hpp
void TipCoordinate :: Z（const float z）{
float z_origin_ = 0-sREFERENCE_SPHERE_RADIUS;
}
我认为Adam Rosenfield的回答解决了我的问题，我已经用一个最小的，完整的例子来替换上面的摘录，再现问题。有人推测，我使用g ++。版本是g ++（Ubuntu / Linaro 4.5.2-8ubuntu4）4.5.2，似乎很可能，优化器受到影响，因为我使用Qt Creator 2.1.0，基于Qt 4.7.2（32位），建于2011年3月11日。这是我的项目文件：
QT - = gui
INCLUDEPATH + = ../src
TEMPLATE = app
SOURCES + = main.cpp \
../src/TipCoordinate.cpp
HEADERS + = \
../src/TipCoordinate.hpp
我的主要文件只是以下内容，但将项目模板更改为lib并删除主文件会导致问题消失。
int main（）{return 0; }我怀疑Qt Creator很重要，因为除了改变模板，当我改变其他看似不相关的问题消失或重新出现。因此，我已经包含了Qt Creator生成的Makefile如下： ############ ################################################## ###############
＃Makefile for building：UnitTest
＃由qmake生成（2.01a）（Qt 4.7.3）on：Sun Oct 14 15： 05:23 2012
＃项目：UnitTest.pro
＃模板：app
＃命令：/usr/local/Trolltech/QtEmbedded-4.7.3/bin/qmake -spec / usr / local / Trolltech / QtEmbedded-4.7.3 / mkspecs / qws / linux-x86-g ++ CONFIG + = debug QMLJSDEBUGGER_PATH = / usr / share / qtcreator / qml / qmljsdebugger -o Makefile UnitTest.pro
###### ################################################## #####################
#######编译器，工具和选项
CC = gcc
CXX = g ++
DEFINES = -DQT_NETWORK_LIB -DQT_CORE_LIB -DQT_SHARED
CFLAGS = -pipe -g -Wall -W -D_REENTRANT $（DEFINES）
CXXFLAGS = -pipe - g -Wall -W -D_REENTRANT $（DEFINES）
INCPATH = -I / usr / local / Trolltech / QtEmbedded-4.7.3 / mkspecs / qws / linux-x86-g ++ -I。 -I / usr / local / Trolltech / QtEmbedded-4.7.3 / include / QtCore -I / usr / local / Trolltech / QtEmbedded-4.7.3 / include / QtNetwork -I / usr / local / Trolltech / QtEmbedded-4.7.3 / include -I ../ src -I。
LINK = g ++
LFLAGS = -Wl，-rpath，/ usr / local / Trolltech / QtEmbedded-4.7.3 / lib
LIBS = $（SUBLIBS）-L / usr / local / Trolltech / QtEmbedded-4.7.3 / lib -lQtNetwork -L / usr / local / Trolltech / QtEmbedded-4.7.3 / lib -lQtCore -lpthread
AR = ar cqs
RANLIB =
QMAKE = /usr/local/Trolltech/QtEmbedded-4.7.3/bin/qmake
TAR = tar -cf
COMPRESS = gzip -9f
COPY = cp -f
SED = sed
COPY_FILE = $（COPY）
COPY_DIR = $（COPY）-r
STRIP = strip
INSTALL_FILE = install -m 644 -p
INSTALL_DIR = $ COPY_DIR）
INSTALL_PROGRAM = install -m 755 -p
DEL_FILE = rm -f
SYMLINK = ln -f -s
DEL_DIR = rmdir
MOVE = mv -f
CHK_DIR_EXISTS = test -d
MKDIR = mkdir -p
#######输出目录
OBJECTS_DIR = ./
#######文件
SOURCES = main.cpp \
../src/TipCoordinate.cpp
OBJECTS = main.o \\ \\
TipCoordinate.o
DIST = /usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/common/g++.conf \
/usr/local/Trolltech/QtEmbedded-4.7 .3 / mkspecs / common / unix.conf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/common/linux.conf \
/ usr / local / Trolltech / QtEmbedded -4.7.3 / mkspecs / common / qws.conf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/qconfig.pri \
/ usr / local / Trolltech / QtEmbedded -4.7.3 / mkspecs / modules / qt_webkit_version.pri \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/qt_functions.prf \
/ usr / local / Trolltech /QtEmbedded-4.7.3/mkspecs/features/qt_config.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/exclusive_builds.prf \
/ usr / local /Trolltech/QtEmbedded-4.7.3/mkspecs/features/default_pre.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/debug.prf \
/ usr /local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/default_post.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/warn_on.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/qt.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/unix/thread.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/moc.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/resources.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/uic.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/yacc .prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/lex.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features /include_source_dir.prf \
UnitTest.pro
QMAKE_TARGET = UnitTest
DESTDIR =
TARGET = UnitTest
第一个：全部
## #####隐含规则
.SUFFIXES：.o .c .cpp .cc .cxx .C
.cpp.o：
$（CXX ）-c $（CXXFLAGS）$（INCPATH）-o$ @$<
.cc.o：
$（CXX）-c $（CXXFLAGS）$（INCPATH）-o$ @$<
.cxx.o：
$（CXX）-c $（CXXFLAGS）$（INCPATH）-o$ @$<
.C.o：
$（CXX）-c $（CXXFLAGS）$（INCPATH）-o$ @$<
.c.o：
$（CC）-c $（CFLAGS）$（INCPATH）-o$ @$<
#######构建规则
all：Makefile $（TARGET）
$（TARGET）：$（OBJECTS）
$（LINK）$（LFLAGS）-o $（TARGET）$（OBJECTS）$（OBJCOMP）$（LIBS）
Makefile：UnitTest.pro / usr / local / Trolltech / QtEmbedded -4.7.3 / mkspecs / qws / linux-x86-g ++ / qmake.conf /usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/common/g++.conf \
/ usr / local / Trolltech /QtEmbedded-4.7.3/mkspecs/common/unix.conf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/common/linux.conf \
/ usr / local /Trolltech/QtEmbedded-4.7.3/mkspecs/common/qws.conf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/qconfig.pri \
/ usr / local /Trolltech/QtEmbedded-4.7.3/mkspecs/modules/qt_webkit_version.pri \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/qt_functions.prf \
的/ usr /local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/qt_config.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/exclusive_builds.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/default_pre.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/debug.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/default_post.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/warn_on.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/qt.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/unix/thread .prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/moc.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features /resources.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/uic.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs /features/yacc.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/lex.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3 /mkspecs/features/include_source_dir.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/lib/libQtNetwork.prl \
/usr/local/Trolltech/QtEmbedded-4.7.3 /lib/libQtCore.prl
$（QMAKE）-spec /usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/qws/linux-x86-g++ CONFIG + = debug QMLJSDEBUGGER_PATH = / usr / share / qtcreator / qml / qmljsdebugger -o Makefile UnitTest.pro
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/common/g++.conf：
/usr/local/Trolltech/QtEmbedded-4.7.3 /mkspecs/common/unix.conf：
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/common/linux.conf：
/usr/local/Trolltech/QtEmbedded-4.7.3 /mkspecs/common/qws.conf：
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/qconfig.pri：
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs /modules/qt_webkit_version.pri：
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/qt_functions.prf：
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs /features/qt_config.prf：
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/exclusive_builds.prf：
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs /features/default_pre.prf：
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/debug.prf：
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs /features/default_post.prf：
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/warn_on.prf：
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs /features/qt.prf：
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/unix/thread.prf：
/usr/local/Trolltech/QtEmbedded-4.7.3 /mkspecs/features/moc.prf：
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/resources.prf：
/usr/local/Trolltech/QtEmbedded-4.7.3 /mkspecs/features/uic.prf：
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/yacc.prf：
/usr/local/Trolltech/QtEmbedded-4.7.3 /mkspecs/features/lex.prf：
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/include_source_dir.prf：
/usr/local/Trolltech/QtEmbedded-4.7.3 /lib/libQtNetwork.prl：
/usr/local/Trolltech/QtEmbedded-4.7.3/lib/libQtCore.prl：
qmake：FORCE
@ $（QMAKE）-spec / usr /local/Trolltech/QtEmbedded-4.7.3/mkspecs/qws/linux-x86-g++ CONFIG + = debug QMLJSDEBUGGER_PATH = / usr / share / qtcreator / qml / qmljsdebugger -o Makefile UnitTest.pro
dist ：
@ $（CHK_DIR_EXISTS）.tmp / UnitTest1.0.0 || $（MKDIR）.tmp / UnitTest1.0.0
$（COPY_FILE）--parents $（SOURCES）$（DIST）.tmp / UnitTest1.0.0 /& $（COPY_FILE）--parents ../src/TipCoordinate.hpp .tmp / UnitTest1.0.0 /&& $（COPY_FILE）--parents main.cpp ../src/TipCoordinate.cpp .tmp / UnitTest1.0.0 /&& （cd`dirname .tmp / UnitTest1.0.0&& $（TAR）UnitTest1.0.0.tar UnitTest1.0.0&& $（COMPRESS）UnitTest1.0.0.tar）&& $（MOVE）`dirname .tmp / UnitTest1.0.0` / UnitTest1.0.0.tar.gz。 &&& $（DEL_FILE）-r .tmp / UnitTest1.0.0
clean：compiler_clean
- $（DEL_FILE）$（OBJECTS）
- $（DEL_FILE）* 〜core * .core
#######子库
distclean：clean
- $（DEL_FILE）$（TARGET ）
- $（DEL_FILE）的Makefile
检查：首先
mocclean：compiler_moc_header_clean compiler_moc_source_clean
mocables：compiler_moc_header_make_all compiler_moc_source_make_all
compiler_moc_header_make_all：
compiler_moc_header_clean：
compiler_rcc_make_all：
compiler_rcc_clean：
compiler_image_collection_make_all：qmake_image_collection.cpp
compiler_image_collection_clean：
- $（ DEL_FILE）qmake_image_collection.cpp
compiler_moc_source_make_all：
compiler_moc_source_clean：
compiler_uic_make_all：
compiler_uic_clean：
compiler_yacc_decl_make_all：
compiler_yacc_decl_clean：
compiler_yacc_impl_make_all：
compiler_yacc_impl_clean：
compiler_lex_make_all：
compiler_lex_clean：
compiler_clean：
####### Compile
main.o：main .cpp
$（CXX）-c $（CXXFLAGS）$（INCPATH）-o main.o main.cpp
TipCoordinate.o：../src/TipCoordinate.cpp .. /src/TipCoordinate.hpp
$（CXX）-c $（CXXFLAGS）$（INCPATH）-o TipCoordinate.o ../src/TipCoordinate.cpp
##### ##安装
安装：FORCE
卸载：FORCE
FORCE：
我看到一个滚动框出现了，但是如果有一种方法让它显得更简洁，我欢迎任何提示。
解决方案您看到的行为与优化器有所不同。无论什么原因，优化器决定优化数学，并在某些情况下用浮点常数替换，但不是所有情况。当它这样做，没有错误发生，因为变量 sREFERENCE_SPHERE_RADIUS 从来没有被引用。
应的来发生的是，你应该让所有的情况下，未定义的引用的错误，因为变量 sREFERENCE_SPHERE_RADIUS 需要给出一个明确的定义外面的类定义。 C ++标准只允许你给一个 static 类成员的初始化器，如果它是整数或枚举类型：
//头文件
类TipCoordinate
{
static const float sREFERENCE_SPHERE_RADIUS; // declaration
};
//源文件
const float TipCoordinate :: sREFERENCE_SPHERE_RADIUS = 12; //定义
从C ++ 03§9.2/ 4：
只有当声明一个 static时， 成员声明器才能包含常量初始化
const 整数或 const 枚举类型的成员（9.4） 9.4.2。
在最新版本的C ++语言C ++ 11中，规则有点松了，可以在声明中定义浮点常量，但必须使用 constexpr 而不是 const 。
Perhaps this is answered out there somewhere and I just don't know the words to search for it. I am trying to understand if I am seeing a bug or if I don't understand the minus operator. Is the assignment of the constant in the header causing the compiler to trip over the '-'?
My project has the following structure, including generated files:
test
├── src
│ ├── TipCoordinate.cpp
│ └── TipCoordinate.hpp
└── UnitTest
├── main.cpp
├── main.o
├── Makefile
├── TipCoordinate.o
├── UnitTest.pro
└── UnitTest.pro.user
I have a constant defined in my class header as follows:
class TipCoordinate{
public:
TipCoordinate() {};
~TipCoordinate() {};
void Z(const float z);
private:
static const float sREFERENCE_SPHERE_RADIUS = 12;
};
The following code in my class cpp file will not compile:
#include "TipCoordinate.hpp"
void TipCoordinate::Z(const float z){
float z_origin_ = -sREFERENCE_SPHERE_RADIUS;
}
I receive the error .../model/TipCoordinate.cpp:143: error: undefined reference to 'TipCoordinate::sREFERENCE_SPHERE_RADIUS'
However, if I just change it as follows then it is perfectly happy:
#include "TipCoordinate.hpp"
void TipCoordinate::Z(const float z){
float z_origin_ = -1*sREFERENCE_SPHERE_RADIUS;
}
Alternatively, this works also:
#include "TipCoordinate.hpp"
void TipCoordinate::Z(const float z){
float z_origin_ = 0-sREFERENCE_SPHERE_RADIUS;
}
I think that Adam Rosenfield's answer addresses my question, but in response to some of the comments I have replaced the above excerpts with a minimal, complete example that reproduces the problem. As some surmised, I am using g++. The version is g++ (Ubuntu/Linaro 4.5.2-8ubuntu4) 4.5.2 and it seems likely that the optimizer is affected because I am using "Qt Creator 2.1.0, Based on Qt 4.7.2 (32 bit), Built on Mar 11 2011". Here is my project file:
QT -= gui
INCLUDEPATH += ../src
TEMPLATE = app
SOURCES += main.cpp \
../src/TipCoordinate.cpp
HEADERS += \
../src/TipCoordinate.hpp
My main file is simply the following, but changing the project template to lib and removing the main file causes the issue to disappear.
int main() { return 0; }
I suspect that Qt Creator matters because in addition to changing the template, when I change other seemingly irrelevant factors the issue disappears or reappears. For that reason, I have included the Qt Creator generated Makefile below:
#############################################################################
# Makefile for building: UnitTest
# Generated by qmake (2.01a) (Qt 4.7.3) on: Sun Oct 14 15:05:23 2012
# Project: UnitTest.pro
# Template: app
# Command: /usr/local/Trolltech/QtEmbedded-4.7.3/bin/qmake -spec /usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/qws/linux-x86-g++ CONFIG+=debug QMLJSDEBUGGER_PATH=/usr/share/qtcreator/qml/qmljsdebugger -o Makefile UnitTest.pro
#############################################################################
####### Compiler, tools and options
CC = gcc
CXX = g++
DEFINES = -DQT_NETWORK_LIB -DQT_CORE_LIB -DQT_SHARED
CFLAGS = -pipe -g -Wall -W -D_REENTRANT $(DEFINES)
CXXFLAGS = -pipe -g -Wall -W -D_REENTRANT $(DEFINES)
INCPATH = -I/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/qws/linux-x86-g++ -I. -I/usr/local/Trolltech/QtEmbedded-4.7.3/include/QtCore -I/usr/local/Trolltech/QtEmbedded-4.7.3/include/QtNetwork -I/usr/local/Trolltech/QtEmbedded-4.7.3/include -I../src -I.
LINK = g++
LFLAGS = -Wl,-rpath,/usr/local/Trolltech/QtEmbedded-4.7.3/lib
LIBS = $(SUBLIBS) -L/usr/local/Trolltech/QtEmbedded-4.7.3/lib -lQtNetwork -L/usr/local/Trolltech/QtEmbedded-4.7.3/lib -lQtCore -lpthread
AR = ar cqs
RANLIB =
QMAKE = /usr/local/Trolltech/QtEmbedded-4.7.3/bin/qmake
TAR = tar -cf
COMPRESS = gzip -9f
COPY = cp -f
SED = sed
COPY_FILE = $(COPY)
COPY_DIR = $(COPY) -r
STRIP = strip
INSTALL_FILE = install -m 644 -p
INSTALL_DIR = $(COPY_DIR)
INSTALL_PROGRAM = install -m 755 -p
DEL_FILE = rm -f
SYMLINK = ln -f -s
DEL_DIR = rmdir
MOVE = mv -f
CHK_DIR_EXISTS= test -d
MKDIR = mkdir -p
####### Output directory
OBJECTS_DIR = ./
####### Files
SOURCES = main.cpp \
../src/TipCoordinate.cpp
OBJECTS = main.o \
TipCoordinate.o
DIST = /usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/common/g++.conf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/common/unix.conf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/common/linux.conf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/common/qws.conf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/qconfig.pri \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/modules/qt_webkit_version.pri \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/qt_functions.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/qt_config.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/exclusive_builds.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/default_pre.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/debug.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/default_post.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/warn_on.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/qt.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/unix/thread.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/moc.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/resources.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/uic.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/yacc.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/lex.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/include_source_dir.prf \
UnitTest.pro
QMAKE_TARGET = UnitTest
DESTDIR =
TARGET = UnitTest
first: all
####### Implicit rules
.SUFFIXES: .o .c .cpp .cc .cxx .C
.cpp.o:
$(CXX) -c $(CXXFLAGS) $(INCPATH) -o "$@" "$<"
.cc.o:
$(CXX) -c $(CXXFLAGS) $(INCPATH) -o "$@" "$<"
.cxx.o:
$(CXX) -c $(CXXFLAGS) $(INCPATH) -o "$@" "$<"
.C.o:
$(CXX) -c $(CXXFLAGS) $(INCPATH) -o "$@" "$<"
.c.o:
$(CC) -c $(CFLAGS) $(INCPATH) -o "$@" "$<"
####### Build rules
all: Makefile $(TARGET)
$(TARGET): $(OBJECTS)
$(LINK) $(LFLAGS) -o $(TARGET) $(OBJECTS) $(OBJCOMP) $(LIBS)
Makefile: UnitTest.pro /usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/qws/linux-x86-g++/qmake.conf /usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/common/g++.conf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/common/unix.conf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/common/linux.conf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/common/qws.conf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/qconfig.pri \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/modules/qt_webkit_version.pri \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/qt_functions.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/qt_config.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/exclusive_builds.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/default_pre.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/debug.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/default_post.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/warn_on.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/qt.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/unix/thread.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/moc.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/resources.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/uic.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/yacc.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/lex.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/include_source_dir.prf \
/usr/local/Trolltech/QtEmbedded-4.7.3/lib/libQtNetwork.prl \
/usr/local/Trolltech/QtEmbedded-4.7.3/lib/libQtCore.prl
$(QMAKE) -spec /usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/qws/linux-x86-g++ CONFIG+=debug QMLJSDEBUGGER_PATH=/usr/share/qtcreator/qml/qmljsdebugger -o Makefile UnitTest.pro
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/common/g++.conf:
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/common/unix.conf:
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/common/linux.conf:
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/common/qws.conf:
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/qconfig.pri:
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/modules/qt_webkit_version.pri:
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/qt_functions.prf:
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/qt_config.prf:
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/exclusive_builds.prf:
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/default_pre.prf:
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/debug.prf:
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/default_post.prf:
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/warn_on.prf:
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/qt.prf:
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/unix/thread.prf:
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/moc.prf:
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/resources.prf:
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/uic.prf:
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/yacc.prf:
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/lex.prf:
/usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/features/include_source_dir.prf:
/usr/local/Trolltech/QtEmbedded-4.7.3/lib/libQtNetwork.prl:
/usr/local/Trolltech/QtEmbedded-4.7.3/lib/libQtCore.prl:
qmake: FORCE
@$(QMAKE) -spec /usr/local/Trolltech/QtEmbedded-4.7.3/mkspecs/qws/linux-x86-g++ CONFIG+=debug QMLJSDEBUGGER_PATH=/usr/share/qtcreator/qml/qmljsdebugger -o Makefile UnitTest.pro
dist:
@$(CHK_DIR_EXISTS) .tmp/UnitTest1.0.0 || $(MKDIR) .tmp/UnitTest1.0.0
$(COPY_FILE) --parents $(SOURCES) $(DIST) .tmp/UnitTest1.0.0/ && $(COPY_FILE) --parents ../src/TipCoordinate.hpp .tmp/UnitTest1.0.0/ && $(COPY_FILE) --parents main.cpp ../src/TipCoordinate.cpp .tmp/UnitTest1.0.0/ && (cd `dirname .tmp/UnitTest1.0.0` && $(TAR) UnitTest1.0.0.tar UnitTest1.0.0 && $(COMPRESS) UnitTest1.0.0.tar) && $(MOVE) `dirname .tmp/UnitTest1.0.0`/UnitTest1.0.0.tar.gz . && $(DEL_FILE) -r .tmp/UnitTest1.0.0
clean:compiler_clean
-$(DEL_FILE) $(OBJECTS)
-$(DEL_FILE) *~ core *.core
####### Sub-libraries
distclean: clean
-$(DEL_FILE) $(TARGET)
-$(DEL_FILE) Makefile
check: first
mocclean: compiler_moc_header_clean compiler_moc_source_clean
mocables: compiler_moc_header_make_all compiler_moc_source_make_all
compiler_moc_header_make_all:
compiler_moc_header_clean:
compiler_rcc_make_all:
compiler_rcc_clean:
compiler_image_collection_make_all: qmake_image_collection.cpp
compiler_image_collection_clean:
-$(DEL_FILE) qmake_image_collection.cpp
compiler_moc_source_make_all:
compiler_moc_source_clean:
compiler_uic_make_all:
compiler_uic_clean:
compiler_yacc_decl_make_all:
compiler_yacc_decl_clean:
compiler_yacc_impl_make_all:
compiler_yacc_impl_clean:
compiler_lex_make_all:
compiler_lex_clean:
compiler_clean:
####### Compile
main.o: main.cpp
$(CXX) -c $(CXXFLAGS) $(INCPATH) -o main.o main.cpp
TipCoordinate.o: ../src/TipCoordinate.cpp ../src/TipCoordinate.hpp
$(CXX) -c $(CXXFLAGS) $(INCPATH) -o TipCoordinate.o ../src/TipCoordinate.cpp
####### Install
install: FORCE
uninstall: FORCE
FORCE:
I see a scroll box has appeared, but if there is a way to make that appear more concise, I welcome any tips.
解决方案 The difference in behavior you're seeing is to the optimizer. For whatever reason, the optimizer decides to optimize out the math and replace it with a floating-point constant in some of the cases, but not all of the cases. When it does that, no error occurs, because the variable sREFERENCE_SPHERE_RADIUS is never referenced anywhere.
What should be happening is that you ought to be getting the "undefined reference" error in all of the cases, because the variable sREFERENCE_SPHERE_RADIUS needs to be given an explicit definition outside of the class definition. The C++ standard only allows you to give an initializer of a static class member if it's of integral or enumerated type:
// Header file
class TipCoordinate
{
static const float sREFERENCE_SPHERE_RADIUS; // declaration
};
// Source file
const float TipCoordinate::sREFERENCE_SPHERE_RADIUS = 12; // definition
From C++03 §9.2/4:
A member-declarator can contain a constant-initializer only if it declares a static member (9.4) of
const integral or const enumeration type, see 9.4.2.
In the latest version of the C++ language, C++11, the rules are a little looser, and you can define floating-point constants in the declaration, but you have to use constexpr instead of const.
这篇关于未定义的引用 - 在C ++中`a = -b;`和`a = -1 * b;`和`a = 0-b'之间应该有区别吗？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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