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| -rw-r--r-- | Lesson_13/README.md | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/Lesson_13/README.md b/Lesson_13/README.md index 5ba6fb3..0d42005 100644 --- a/Lesson_13/README.md +++ b/Lesson_13/README.md @@ -58,9 +58,31 @@ ShellAppMain ( IN CHAR16 **Argv ); ``` +You can look at the source code of `ShellAppMain` at the https://github.com/tianocore/edk2/blob/master/ShellPkg/Library/UefiShellCEntryLib/UefiShellCEntryLib.c +If you look at the source you could see that istead of a `HandleProtocol` API that we've used: +``` +Status = gBS->HandleProtocol( + ImageHandle, + &gEfiShellParametersProtocolGuid, + (VOID **) &ShellParameters +); +``` +it uses `OpenProtocol` API: (I've modified a code a little bit to make it comparable to our version) +``` +Status = gBS->OpenProtocol( + ImageHandle, + &gEfiShellParametersProtocolGuid, + (VOID **)&ShellParameters, + ImageHandle, + NULL, + EFI_OPEN_PROTOCOL_GET_PROTOCOL +); +``` +According to the UEFI spec `HandleProtocol` API is outdated and `OpenProtocol` should be used instead. +`OpenProtocol` API is a more general call that can cover more cases. It all would matter when you start develop UEFI drivers. You can read UEFI spec for more information. Right now just accept a fact that for the UEFI app these two calls are the same. -To find the necessary `ShellCEntryLib` library class search as usual: +Let's go back to our code. To find the necessary `ShellCEntryLib` library class search as usual: ``` $ grep ShellCEntryLib -r ./ --include=*.inf | grep LIBRARY_CLASS ./ShellPkg/Library/UefiShellCEntryLib/UefiShellCEntryLib.inf: LIBRARY_CLASS = ShellCEntryLib|UEFI_APPLICATION UEFI_DRIVER |