diff options
Diffstat (limited to 'Lessons')
| -rw-r--r-- | Lessons/Lesson_48/README.md | 57 | ||||
| -rw-r--r-- | Lessons/Lesson_48/UefiLessonsPkg/HIIStringsUNI/HIIStringsUNI.c | 6 |
2 files changed, 63 insertions, 0 deletions
diff --git a/Lessons/Lesson_48/README.md b/Lessons/Lesson_48/README.md index 850c218..68adf6e 100644 --- a/Lessons/Lesson_48/README.md +++ b/Lessons/Lesson_48/README.md @@ -392,3 +392,60 @@ You can see now how important to reference our strings with the `STRING_TOKEN` m // #define STRING_TOKEN(t) t ``` + +# Best language + +The `HiiGetString` library function not only simplier to use over direct protocol use, it has another useful feature. +It is possible to call `HiiGetString` without providing target language. This way function would decide itself what language is better to use. +This way the best language would be chosen based on the value of the `PlatformLang` runtime variable. +Remember how we used `gRT->GetNextVariableName`/`gRT->GetVariable` to work with the runtime variables? `PlatformLang` was one of them. With the help of our `ListVariables.efi` application we've discovered that this option is placed under the `gEfiGlobalVariableGuid`. + +8BE4DF61-93CA-11D2-AA0D-00E098032B8C - gEfiGlobalVariableGuid +https://github.com/tianocore/edk2/blob/master/MdePkg/Include/Guid/GlobalVariable.h + +https://github.com/tianocore/edk2/blob/master/MdePkg/MdePkg.dec + + +Let's add these strings at the end of our application: +``` +Print(L"Best language ID=1: %s\n", HiiGetString(Handle, 1, NULL)); +Print(L"Best language ID=2: %s\n", HiiGetString(Handle, STRING_TOKEN(STR_HELLO), NULL)); +Print(L"Best langiage ID=3: %s\n", HiiGetString(Handle, STRING_TOKEN(STR_BYE), NULL)); +``` + +Now build and run our application under OVMF: +``` +FS0:\> HIIStringsUNI.efi +en-US ID=1: English +en-US ID=2: Hello! +en-US ID=3: Bye! +fr-FR ID=1: Francais +fr-FR ID=2: Bonjour! +fr-FR ID=3: Au revoir! +Best language ID=1: English +Best language ID=2: Hello! +Best language ID=3: Bye! +``` +Now execute `exit` in the UEFI shell to go to the BIOS settings. Change language to French. Close QEMU and re-run it again. Now the output for best language would be coming from the `fr-FR` String package: +``` +FS0:\> HIIStringsUNI.efi +en-US ID=1: English +en-US ID=2: Hello! +en-US ID=3: Bye! +fr-FR ID=1: Francais +fr-FR ID=2: Bonjour! +fr-FR ID=3: Au revoir! +Best language ID=1: Francais +Best language ID=2: Bonjour! +Best language ID=3: Au revoir! +``` + +Another useful feature that it is possible to call `HiiGetString` with more general language names. For example `fr` instead of `fr-FR` will still choose the correct String package. +``` + Print(L"fr ID=3: %s\n", HiiGetString(Handle, STRING_TOKEN(STR_BYE), "fr")); +``` +This will print: +``` +fr ID=3: Au revoir! +``` +Keep in mind that this functionality comes purely from the `HiiGetString` implementation. If you would try to paste "fr" instead of "fr-FR" to the `EFI_HII_STRING_PROTOCOL.GetString()` you simply get an error. diff --git a/Lessons/Lesson_48/UefiLessonsPkg/HIIStringsUNI/HIIStringsUNI.c b/Lessons/Lesson_48/UefiLessonsPkg/HIIStringsUNI/HIIStringsUNI.c index 160108b..6d6123d 100644 --- a/Lessons/Lesson_48/UefiLessonsPkg/HIIStringsUNI/HIIStringsUNI.c +++ b/Lessons/Lesson_48/UefiLessonsPkg/HIIStringsUNI/HIIStringsUNI.c @@ -28,5 +28,11 @@ UefiMain ( Print(L"fr-FR ID=2: %s\n", HiiGetString(Handle, STRING_TOKEN(STR_HELLO), "fr-FR")); Print(L"fr-FR ID=3: %s\n", HiiGetString(Handle, STRING_TOKEN(STR_BYE), "fr-FR")); + Print(L"Best language ID=1: %s\n", HiiGetString(Handle, 1, NULL)); + Print(L"Best language ID=2: %s\n", HiiGetString(Handle, STRING_TOKEN(STR_HELLO), NULL)); + Print(L"Best language ID=3: %s\n", HiiGetString(Handle, STRING_TOKEN(STR_BYE), NULL)); + + Print(L"fr ID=3: %s\n", HiiGetString(Handle, STRING_TOKEN(STR_BYE), "fr")); + return EFI_SUCCESS; } |