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Diffstat (limited to 'winsup/cygwin/include/exceptions.h')
| -rw-r--r-- | winsup/cygwin/include/exceptions.h | 120 |
1 files changed, 0 insertions, 120 deletions
diff --git a/winsup/cygwin/include/exceptions.h b/winsup/cygwin/include/exceptions.h deleted file mode 100644 index 462000d61..000000000 --- a/winsup/cygwin/include/exceptions.h +++ /dev/null @@ -1,120 +0,0 @@ -/* exceptions.h - - Copyright 1996, 1997, 1998, 2001 Red Hat, Inc. - -This file is part of Cygwin. - -This software is a copyrighted work licensed under the terms of the -Cygwin license. Please consult the file "CYGWIN_LICENSE" for -details. */ - -#ifndef _EXCEPTIONS_H -#define _EXCEPTIONS_H - -#ifdef __cplusplus -extern "C" { -#endif /* __cplusplus */ - -/* Documentation on the innards of exception handling (i.e. from the - perspective of a compiler implementor) apparently doesn't exist. Sigh. - However, the following came from Onno Hovers <onno@stack.urc.tue.nl> - -The first pointer to the chain of handlers is in the thread environment block -at FS:[0]. This chain has the following format: - -typedef struct __EXCEPTION_FRAME -{ - struct __EXCEPTION_FRAME *Prev; /-* pointer to the previous frame *-/ - PEXCEPTION_HANDLER Handler; /-* handler function *-/ -} - -You register an exception handler in your compiler with this simple ASM -sequence: - PUSH _MyExceptionHandler - PUSH FS:[0] - MOV FS:[0],ESP -An exception frame MUST be on the stack! The frame may have more fields and -both Visual C++ and Borland C++ use more fields for themselves. - -When an exception occurs the system calls all handlers starting with the -handler at FS:0, and then the previous etc. until one handler returns -ExceptionContinueExecution, which is 0. If a handler does not want to handle -the exception it should just return ExceptionContinueSearch, which is 1. - -The handler has the following parameters: -ehandler ( - PEXCEPTION_RECORD erecord, - PEXCEPTION_FRAME myframe, - PCONTEXT context, /-* context before and after *-/ - PVOID dispatch) /-* something *-/ - -When a handler wants to handle the exception, it has some alternatives: - --one is to do do something about the exception condition, like emulating -an invalid instruction, mapping memory where there was a page fault, etc. -If the handler wants to have the context of the thread that causes the -exception changed, it should make that change in the context passed to the -handler. - --the second alternative is to call all exception handlers again, indicating -that you want them to clean up. This way all the __finally blocks get -executed. After doing that you change the context passed to the handler so -the code starts executing in the except block. For this purpose you could -call RtlUnwind. This (undocumented) function calls all exception handlers -up to but not including the exception frame passed to it. If NULL is passed -as exception frame RtlUnwind calls all exception handlers and then exits the -process. The parameters to RtlUnwind are: - -RtlUnwind ( - PEXCEPTION_FRAME endframe, - PVOID unusedEip, - PEXCEPTION_RECORD erecord, - DWORD returnEax) - -You should set unusedEip to the address where RtlUnwind should return like -this: - PUSH 0 - PUSH OFFSET ReturnUnwind - PUSH 0 - PUSH 0 - CALL RtlUnwind -ReturnUnwind: - ..... - -If no EXCEPTION_RECORD is passed, RtlUnwind makes a default exception -record. In any case, the ExceptionFlags part of this record has the -EH_UNWINDING (=2), flag set. (and EH_EXIT_UNWIND (=4), when NULL is passed as the end -frame.). - -The handler for a exception as well as a for unwinds may be executed in the -thread causing the exception, but may also be executed in another (special -exception) thread. So it is not wise to make any assumptions about that! - -As an alternative you may consider the SetUnhandledExceptionFilter API -to install your own exception filter. This one is documented. -*/ - -/* The January 1994 MSJ has an article entitled "Clearer, More Comprehensive - Error Processing with Win32 Structured Exception Handling". It goes into - a teensy bit of detail of the innards of exception handling (i.e. what we - have to do). */ - -typedef int (exception_handler) - (EXCEPTION_RECORD *, void *, CONTEXT *, void *); - -typedef struct _exception_list -{ - struct _exception_list *prev; - exception_handler *handler; - - /* We're apparently free to add more stuff here. - At present we don't need any. */ -} exception_list; - -void init_exceptions (exception_list *); - -#ifdef __cplusplus -}; -#endif /* __cplusplus */ - -#endif /* _EXCEPTIONS_H */ |