makefile - "Sysroot"从 QtCreator 传输到 Makefile 中的哪个命令？

Question

我正在使用 Qmake 和 QtCreator 进行交叉编译。在套件的设置中(工具链和 qmake 的详细信息在那里设置)有一个名为 Sysroot: 的字段。 .
( Example here )

由于 QtCreator 和 Qmake 最后负责生成 Makefile，我的问题是，该选项在 Makefile 中转换为什么以及它如何传递给工具链？

提问的动机

我有 Sysroot:指向 ~/path-to-sysroot . ~/path-to-sysroot包含为嵌入式目标交叉编译的常规 sysroot 结构。

~/path-to-sysroot
   ├── bin
   ├── include
   ├── lib
   ├── sbin
   ├── share
   └── usr

当我尝试交叉编译一些依赖于 ~/path-to-sysroot/usr/lib 中的库的代码时，它失败并显示缺少库的消息，但存在库。我解析了生成的makefile，没有发现~/path-to-sysroot/usr/lib的痕迹.

Answer 1

来自:http://doc.qt.io/qt-5/qt-conf.html

qt.conf 文件可用于覆盖编译到 Qt 库中的硬编码路径。可以使用 QLibraryInfo 类访问这些路径。如果没有 qt.conf，QLibraryInfo 中的函数会返回这些硬编码的路径；否则它们返回 qt.conf 中指定的路径。

如果没有 qt.conf，Qt 库将使用硬编码路径来查找插件、翻译等。这些路径可能不存在于目标系统上，或者它们可能无法访问。因此，您可能需要 qt.conf 来使 Qt 库看起来别处。

qmake -query
QT_SYSROOT:/home/mentor/work/git/mel_repos/mel_cedar/build/tmp/sysroots/x86_64-linux
QT_INSTALL_PREFIX:/home/mentor/work/git/mel_repos/mel_cedar/build/tmp/sysroots/x86_64-linux/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr
QT_INSTALL_PREFIX/raw:/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr
QT_INSTALL_ARCHDATA:/home/mentor/work/git/mel_repos/mel_cedar/build/tmp/sysroots/x86_64-linux/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/lib/qt5
QT_INSTALL_ARCHDATA/raw:/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/lib/qt5
QT_INSTALL_DATA:/home/mentor/work/git/mel_repos/mel_cedar/build/tmp/sysroots/x86_64-linux/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/share/qt5
QT_INSTALL_DATA/raw:/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/share/qt5
QT_INSTALL_DOCS:/home/mentor/work/git/mel_repos/mel_cedar/build/tmp/sysroots/x86_64-linux/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/share/doc/qt5
QT_INSTALL_DOCS/raw:/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/share/doc/qt5
QT_INSTALL_HEADERS:/home/mentor/work/git/mel_repos/mel_cedar/build/tmp/sysroots/x86_64-linux/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/include/qt5
QT_INSTALL_HEADERS/raw:/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/include/qt5
QT_INSTALL_LIBS:/home/mentor/work/git/mel_repos/mel_cedar/build/tmp/sysroots/x86_64-linux/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/lib
QT_INSTALL_LIBS/raw:/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/lib
QT_INSTALL_LIBEXECS:/home/mentor/work/git/mel_repos/mel_cedar/build/tmp/sysroots/x86_64-linux/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/lib/qt5/libexec
QT_INSTALL_LIBEXECS/raw:/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/lib/qt5/libexec
QT_INSTALL_BINS:/home/mentor/work/git/mel_repos/mel_cedar/build/tmp/sysroots/x86_64-linux/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/bin/qt5
QT_INSTALL_BINS/raw:/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/bin/qt5
QT_INSTALL_TESTS:/home/mentor/work/git/mel_repos/mel_cedar/build/tmp/sysroots/x86_64-linux/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/share/qt5/tests
QT_INSTALL_TESTS/raw:/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/share/qt5/tests
QT_INSTALL_PLUGINS:/home/mentor/work/git/mel_repos/mel_cedar/build/tmp/sysroots/x86_64-linux/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/lib/qt5/plugins
QT_INSTALL_PLUGINS/raw:/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/lib/qt5/plugins
QT_INSTALL_IMPORTS:/home/mentor/work/git/mel_repos/mel_cedar/build/tmp/sysroots/x86_64-linux/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/lib/qt5/imports
QT_INSTALL_IMPORTS/raw:/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/lib/qt5/imports
QT_INSTALL_QML:/home/mentor/work/git/mel_repos/mel_cedar/build/tmp/sysroots/x86_64-linux/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/lib/qt5/qml
QT_INSTALL_QML/raw:/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/lib/qt5/qml
QT_INSTALL_TRANSLATIONS:/home/mentor/work/git/mel_repos/mel_cedar/build/tmp/sysroots/x86_64-linux/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/share/qt5/translations
QT_INSTALL_TRANSLATIONS/raw:/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/share/qt5/translations
QT_INSTALL_CONFIGURATION:/home/mentor/work/git/mel_repos/mel_cedar/build/tmp/sysroots/x86_64-linux/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/etc/qt5
QT_INSTALL_CONFIGURATION/raw:/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/etc/qt5
QT_INSTALL_EXAMPLES:/home/mentor/work/git/mel_repos/mel_cedar/build/tmp/sysroots/x86_64-linux/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/examples
QT_INSTALL_EXAMPLES/raw:/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/examples
QT_INSTALL_DEMOS:/home/mentor/work/git/mel_repos/mel_cedar/build/tmp/sysroots/x86_64-linux/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/examples
QT_INSTALL_DEMOS/raw:/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/examples
QT_HOST_PREFIX:/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr
QT_HOST_DATA:/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/lib/qt5
QT_HOST_BINS:/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/bin/qt5
QT_HOST_LIBS:/opt/mel/next+snapshot/sysroots/i686-melsdk-linux/usr/lib
QT_EXTERNAL_HOST_BINS:/home/mentor/work/git/mel_repos/mel_cedar/build/tmp/sysroots/x86_64-linux/usr/bin/qt5
QMAKE_SPEC:/home/mentor/work/git/mel_repos/mel_cedar/build/tmp/sysroots/x86_64-linux/usr/lib/qt5/mkspecs/linux-oe-g++
QMAKE_XSPEC:linux-oe-g++
QMAKE_VERSION:3.0
QT_VERSION:5.4.1

qmake 不使用 sysroot 参数，它包含所有路径。您可以通过覆盖 qt.conf 中的这些路径来自定义 qmake，但它仍然没有显示 sysroot 的路径。而且我认为它没有任何选项可以指定 sysroot。您必须在 qtcreator 的编译器标志中手动设置 sysroot