qt - Qt 是否强制系统语言环境？

Question

以下示例似乎显示了 Qt 中的一个错误。还是我弄错了？

std::cout << atof("0.456") << std::endl; // OK prints 0.456
QApplication app (argc, argv);
//QLocale::setDefault(QLocale::C); // No effect at all.
std::cout << atof("0.456") << std::endl; // do not work on on fr_FR.UTF-8, print 0.

当使用非标准语言环境时，在我的示例 fr_FR.UTF-8 中，创建 QApplication 似乎会更改系统语言环境，因为 atof 使用它来进行转换。

在我看来，创建 QApplication 会提取系统语言环境并使用它调用 setenv。

Answer 1

来自 Qt 文档

Locale Settings

On Unix/Linux Qt is configured to use the system locale settings by default. This can cause a conflict when using POSIX functions, for instance, when converting between data types such as floats and strings, since the notation may differ between locales. To get around this problem, call the POSIX function setlocale(LC_NUMERIC,"C") right after initializing QApplication or QCoreApplication to reset the locale that is used for number formatting to "C"-locale.