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|Home > Image Structure and Generation > Command-line options used to control the generation of C++ exception tables|
You can control the generation of C++ exception tables using command-line options.
By default, or if the option
specified, the image can contain exception tables. Exception tables are discarded silently
if no code throws an exception. However, if the option
--no_exceptions is specified, the linker generates an error if any exceptions
tables are present after unused sections have been eliminated.
You can use the
--no_exceptions option to ensure that your code is
exceptions free. The linker generates an error message to highlight that exceptions have
been found and does not produce a final image.
However, you can use the
--no_exceptions option with the
--diag_warning option to downgrade the error message to a warning. The
linker produces a final image but also generates a message to warn you that exceptions have
The linker can create exception tables for legacy objects that contain debug frame
information. The linker can do this safely for C and assembly language objects. By default,
the linker does not create exception tables. This is the same as using the linker option
The linker option
--exceptions_tables=unwind enables the linker to use the
.debug_frame information to create a register-restoring unwinding table
for each section in your image that does not already have an exception table. If this is not
possible, the linker creates a nounwind table instead.
Use the linker option
--exceptions_tables=cantunwind to create a nounwind
table for each section in your image that does not already have an exception table.
Be aware of the following:
With the default settings, that is,
--exceptions_tables=nocreate, it is not safe to throw an exception through
C or assembly code, unless the C code is compiled with the option
The linker can generate frame unwinding instructions from objects with
.debug_frame information. Frame unwinding is sufficient for C and
assembler code. It is not sufficient for C++ code, because it does not call the
destructors for the objects on the stack that is being unwound.
The cleanup code for C++ must be generated by the compiler with the