2016-12-15

undefined reference to `<クラス名>::<シグナル名>'

Qt 4.8

問題

シグナルを定義してビルドすると下記のエラーが発生する。

undefined reference to `<クラス名>::<シグナル名>'

原因

クラス定義に Q_OBJECT キーワードを記述していないため。

対策

クラス定義に Q_OBJECT キーワードを記述する。

class MyClass
{
    Q_OBJECT
    ...
signals:
    void MySignal();
    ...
}

参考文献

c++ - qt signal undefined reference error - Stack Overflow

2016-12-14

ウィンドウ名からウィンドウ ID を得る

X11

xwininfo コマンドを使う。

xwininfo -name NAME

wmctrl コマンドの結果をフィルターする。

wmctrl -l | grep "NAME"

2016-12-06

ERROR: ExpansionError during parsing ...: Failure expanding variable do_unpack: SyntaxError: invalid syntax ...

Yocto Project

問題

レシピに do_unpack_append を追加すると、do_unpack 実行時にエラーになる。

レシピ：

do_unpack_append(){
    rm obstacle.file
}

エラー：

ERROR: ExpansionError during parsing ...: Failure expanding variable do_unpack: SyntaxError: invalid syntax ...

原因

内容が Python で書かれていないため。

do_unpack は Python 関数のため、do_unpack_append も Python で記述する必要がある。

対処

Python で書く。

do_unpack_append(){
    os.remove("obstacle.file")
}

2016-11-30

　objcopy failed with exit code 256　...: File format not recognized

Yocto Project

問題

package タスクが次のエラーで失敗する。

ERROR: objcopy failed with exit code 256 (cmd was 'arm-poky-linux-gnueabi-objcopy' --only-keep-debug '/path/to/workdir/package/usr/bin/example' '/path/to/workdir/package/usr/bin/.debug/example'):
arm-poky-linux-gnueabi-objcopy:/path/to/workdir/package/usr/bin/example: File format not recognized
ERROR: Function failed: split_and_strip_files
ERROR: Logfile of failure stored in: /path/to/workdir/temp/log.do_package.12345
ERROR: Task 10 (/path/to/recipe/example_0.1.bb, do_package) failed with exit code '1'

原因

ソースの tar ボールにセルフビルドした時の実行ファイルが含まれていたため。

対処

tar ボールからセルフビルド向けファイルを削除した。

2016-11-30

タスクの一覧を表示する方法

Yocto Project

bitbake コマンドで listtasks タスクを実行する。

なお、表示されたタスクが実行されるとは限らないようだ。

$ bitbake -c listtasks <レシピ名>

$ bitbake -c listtasks core-image-minimal
do_build                       Default task for a recipe - depends on all other normal tasks required to 'build' a recipe
do_bundle_initramfs            Combines an initial ramdisk image and kernel together to form a single image
do_checkuri                    Validates the SRC_URI value
do_checkuriall                 Validates the SRC_URI value for all recipes required to build a target
do_clean                       Removes all output files for a target
do_cleanall                    Removes all output files, shared state cache, and downloaded source files for a target
do_cleansstate                 Removes all output files and shared state cache for a target
do_compile                     Compiles the source in the compilation directory
do_configure                   Configures the source by enabling and disabling any build-time and configuration options for the software being built
do_devshell                    Starts a shell with the environment set up for development/debugging
do_fetch                       Fetches the source code
do_fetchall                    Fetches all remote sources required to build a target
do_install                     Copies files from the compilation directory to a holding area
do_listtasks                   Lists all defined tasks for a target
do_package                     Analyzes the content of the holding area and splits it into subsets based on available packages and files
do_package_setscene            Analyzes the content of the holding area and splits it into subsets based on available packages and files (setscene version)
do_package_write_rpm           Creates the actual RPM packages and places them in the Package Feed area
do_package_write_rpm_setscene  Creates the actual RPM packages and places them in the Package Feed area (setscene version)
do_packagedata                 Creates package metadata used by the build system to generate the final packages
do_packagedata_setscene        Creates package metadata used by the build system to generate the final packages (setscene version)
do_patch                       Locates patch files and applies them to the source code
do_populate_lic                Writes license information for the recipe that is collected later when the image is constructed
do_populate_lic_setscene       Writes license information for the recipe that is collected later when the image is constructed (setscene version)
do_populate_sdk                Creates the file and directory structure for an installable SDK
do_populate_sysroot            Copies a subset of files installed by do_install into the sysroot in order to make them available to other recipes
do_populate_sysroot_setscene   Copies a subset of files installed by do_install into the sysroot in order to make them available to other recipes (setscene version)
do_rootfs                      Creates the root filesystem (file and directory structure) for an image
do_unpack                      Unpacks the source code into a working directory
NOTE: Tasks Summary: Attempted 1 tasks of which 0 didn't need to be rerun and all succeeded.