[英]Unix Qt 5.6 QSettings cannot find QSettings::SystemScope configuration file
链接到Qt Bug报告 : QTBUG-53313
从Qt 5.5迁移到Qt 5.6会出现QSettings的问题,它无法在系统范围内找到QSettings配置文件。 在下面的main.cpp中,QSettings以各种方式初始化,然后查询其属性:
// File: main.cpp
#include <QApplication>
#include <QDebug>
#include <QSettings>
#include <QCoreApplication>
#define ASSUMED_SYSTEM_CONFIG "/etc/xdg/TheOrg/TheApp.conf"
#define ASSUMED_USER_CONFIG "/home/user/.config/TheOrg/TheApp.conf"
void print_info(const QSettings& settings, const char& use_case);
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
QCoreApplication::setOrganizationName("TheOrg");
QCoreApplication::setApplicationName("TheApp");
QSettings settings_a;
QSettings settings_b("TheOrg", "TheApp");
QSettings settings_c(QSettings::SystemScope, "TheOrg", "TheApp");
QSettings settings_d(QSettings::NativeFormat, QSettings::SystemScope, "TheOrg", "TheApp");
print_info(settings_a, 'a');
print_info(settings_b, 'b');
print_info(settings_c, 'c');
print_info(settings_d, 'd');
return a.exec();
}
void print_info(const QSettings& settings, const char& use_case)
{
int value = settings.value("the_value").toInt();
qDebug() << "Using case (" << use_case << ")";
qDebug() << "The value is " << value;
qDebug() << "Settings scope is: " << ((settings.scope() == QSettings::SystemScope) ? "System" : "User");
qDebug() << "Settings organization is: " << settings.organizationName();
qDebug() << "Settings application name is: " << settings.applicationName();
qDebug() << "Settings fallbackEnabled is: " << settings.fallbacksEnabled();
qDebug() << "Settings filename is: " << settings.fileName() << "\n";
}
系统上不存在 ASSUMED_USER_CONFIG文件。
ASSUMED_SYSTEM_CONFIG文件确实存在于系统中,包含:
the_value = 42
用Qt 5.5编译,程序返回:
Using case ( a )
The value is 42
Settings scope is: User
Settings organization is: "TheOrg"
Settings application name is: "TheApp"
Settings fallbackEnabled is: true
Settings filename is: "/home/user/.config/TheOrg/TheApp.conf"
Using case ( b )
The value is 42
Settings scope is: User
Settings organization is: "TheOrg"
Settings application name is: "TheApp"
Settings fallbackEnabled is: true
Settings filename is: "/home/user/.config/TheOrg/TheApp.conf"
Using case ( c )
The value is 42
Settings scope is: System
Settings organization is: "TheOrg"
Settings application name is: "TheApp"
Settings fallbackEnabled is: true
Settings filename is: "/etc/xdg/TheOrg/TheApp.conf"
Using case ( d )
The value is 42
Settings scope is: System
Settings organization is: "TheOrg"
Settings application name is: "TheApp"
Settings fallbackEnabled is: true
Settings filename is: "/etc/xdg/TheOrg/TheApp.conf"
用Qt 5.6编译,程序返回:
Using case ( a )
The value is 0
Settings scope is: User
Settings organization is: "TheOrg"
Settings application name is: "TheApp"
Settings fallbackEnabled is: true
Settings filename is: "/home/user/.config/TheOrg/TheApp.conf"
Using case ( b )
The value is 0
Settings scope is: User
Settings organization is: "TheOrg"
Settings application name is: "TheApp"
Settings fallbackEnabled is: true
Settings filename is: "/home/user/.config/TheOrg/TheApp.conf"
Using case ( c )
The value is 0
Settings scope is: System
Settings organization is: "TheOrg"
Settings application name is: "TheApp"
Settings fallbackEnabled is: true
Settings filename is: "/home/user/Qt5.6/5.6/gcc_64/etc/xdg/TheOrg/TheApp.conf"
Using case ( d )
The value is 0
Settings scope is: System
Settings organization is: "TheOrg"
Settings application name is: "TheApp"
Settings fallbackEnabled is: true
Settings filename is: "/home/user/Qt5.6/5.6/gcc_64/etc/xdg/TheOrg/TheApp.conf"
这里有一些问题:
当使用Qt 5.5编译时,设置'文件名'将按预期构造为所有情况(a,b,c,d)。 由于ASSUMED_USER_CONFIG文件不存在,因此'a'和'b'会回退到ASSUMED_SYSTEM_CONFIG文件。 因此,可以从设置文件中正确检索“the_value”。
但是,当使用Qt 5.6进行编译时,对于'c'和'd'(正确的路径被附加到“/home/user/Qt5.6/5.6/gcc_64”),设置'filename'似乎构造不正确。 因此,无法从设置文件中检索“the_value”。
我没有覆盖Qt Creator中的任何默认环境变量,Qt维护工具自动安装Qt 5.6。 我知道我可以使用环境变量XDG_CONFIG_HOME来设置QSettings :: SystemScope文件的绝对路径,但我认为不应该这样做。
要重述主要问题,如何在QSettings中使用ASSUMED_SYSTEM_CONFIG文件(即QSettings :: SystemScope)?
还有其他人反对这个吗? 我在两台不同的机器上测试了这个。
这是预编译的Linux二进制文件的问题。 如果从源代码编译Qt 5.6,可以通过使用标志'-sysconfdir = / etc'编译Qt来避免此问题。
如果这不是一个选项,您可以设置环境变量XDG_CONFIG_HOME。
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