-@c Copyright (C) 2008-2019 Free Software Foundation, Inc.
+@c Copyright (C) 2008--2020 Free Software Foundation, Inc.
@c Permission is granted to copy, distribute and/or modify this document
@c under the terms of the GNU Free Documentation License, Version 1.3 or
@c any later version published by the Free Software Foundation; with the
using Python.
* Lazy Strings In Python:: Python representation of lazy strings.
* Architectures In Python:: Python representation of architectures.
+* TUI Windows In Python:: Implementing new TUI windows.
@end menu
@node Basic Python
value pointed to by @code{foo}.
A similar function @code{Value.referenced_value} exists which also
-returns @code{gdb.Value} objects corresonding to the values pointed to
+returns @code{gdb.Value} objects corresponding to the values pointed to
by pointer values (and additionally, values referenced by reference
values). However, the behavior of @code{Value.dereference}
differs from @code{Value.referenced_value} by the fact that the
@code{TYPE_CODE_} constants defined below.
@end defvar
+@defvar Type.dynamic
+A boolean indicating whether this type is dynamic. In some
+situations, such as Rust @code{enum} types or Ada variant records, the
+concrete type of a value may vary depending on its contents. That is,
+the declared type of a variable, or the type returned by
+@code{gdb.lookup_type} may be dynamic; while the type of the
+variable's value will be a concrete instance of that dynamic type.
+
+For example, consider this code:
+@smallexample
+int n;
+int array[n];
+@end smallexample
+
+Here, at least conceptually (whether your compiler actually does this
+is a separate issue), examining @w{@code{gdb.lookup_symbol("array", ...).type}}
+could yield a @code{gdb.Type} which reports a size of @code{None}.
+This is the dynamic type.
+
+However, examining @code{gdb.parse_and_eval("array").type} would yield
+a concrete type, whose length would be known.
+@end defvar
+
@defvar Type.name
The name of this type. If this type has no name, then @code{None}
is returned.
@defvar Type.sizeof
The size of this type, in target @code{char} units. Usually, a
target's @code{char} type will be an 8-bit byte. However, on some
-unusual platforms, this type may have a different size.
+unusual platforms, this type may have a different size. A dynamic
+type may not have a fixed size; in this case, this attribute's value
+will be @code{None}.
@end defvar
@defvar Type.tag
@item bitpos
This attribute is not available for @code{enum} or @code{static}
(as in C@t{++}) fields. The value is the position, counting
-in bits, from the start of the containing type.
+in bits, from the start of the containing type. Note that, in a
+dynamic type, the position of a field may not be constant. In this
+case, the value will be @code{None}. Also, a dynamic type may have
+fields that do not appear in a corresponding concrete type.
@item enumval
This attribute is only available for @code{enum} fields, and its value
class MyUnwinder(Unwinder):
def __init__(....):
- supe(MyUnwinder, self).__init___(<expects unwinder name argument>)
+ super(MyUnwinder, self).__init___(<expects unwinder name argument>)
def __call__(pending_frame):
if not <we recognize frame>:
@findex gdb.Inferior
Programs which are being run under @value{GDBN} are called inferiors
-(@pxref{Inferiors and Programs}). Python scripts can access
+(@pxref{Inferiors Connections and Programs}). Python scripts can access
information about and manipulate inferiors controlled by @value{GDBN}
via objects of the @code{gdb.Inferior} class.
is no selected thread, this will return @code{None}.
@end defun
+To get the list of threads for an inferior, use the @code{Inferior.threads()}
+method. @xref{Inferiors In Python}.
+
A @code{gdb.InferiorThread} object has the following attributes:
@defvar InferiorThread.name
@kbd{help tracepoints} at the @value{GDBN} prompt to see a list of
commands in this category.
+@findex COMMAND_TUI
+@findex gdb.COMMAND_TUI
+@item gdb.COMMAND_TUI
+The command has to do with the text user interface (@pxref{TUI}).
+Type @kbd{help tui} at the @value{GDBN} prompt to see a list of
+commands in this category.
+
@findex COMMAND_USER
@findex gdb.COMMAND_USER
@item gdb.COMMAND_USER
of an address space.
It consists of all of the objfiles of the program.
@xref{Objfiles In Python}.
-@xref{Inferiors and Programs, program spaces}, for more details
+@xref{Inferiors Connections and Programs, program spaces}, for more details
about program spaces.
The following progspace-related functions are available in the
@findex gdb.current_progspace
@defun gdb.current_progspace ()
This function returns the program space of the currently selected inferior.
-@xref{Inferiors and Programs}. This is identical to
+@xref{Inferiors Connections and Programs}. This is identical to
@code{gdb.selected_inferior().progspace} (@pxref{Inferiors In Python}) and is
included for historical compatibility.
@end defun
gdb.events.new_objfile.connect(new_objfile_handler)
end
(gdb) file /tmp/hello
-Reading symbols from /tmp/hello...done.
+Reading symbols from /tmp/hello...
Computing the answer to the ultimate question ...
(gdb) python print gdb.current_progspace().expensive_computation
42
gdb.events.new_objfile.connect(new_objfile_handler)
end
(gdb) file ./hello
-Reading symbols from ./hello...done.
+Reading symbols from ./hello...
(gdb) python print gdb.objfiles()[0].time_loaded
2014-10-09 11:41:36.770345
@end smallexample
from a different place.
@end defun
+@defun Objfile.lookup_global_symbol (name @r{[}, domain@r{]})
+Search for a global symbol named @var{name} in this objfile. Optionally, the
+search scope can be restricted with the @var{domain} argument.
+The @var{domain} argument must be a domain constant defined in the @code{gdb}
+module and described in @ref{Symbols In Python}. This function is similar to
+@code{gdb.lookup_global_symbol}, except that the search is limited to this
+objfile.
+
+The result is a @code{gdb.Symbol} object or @code{None} if the symbol
+is not found.
+@end defun
+
+@defun Objfile.lookup_static_symbol (name @r{[}, domain@r{]})
+Like @code{Objfile.lookup_global_symbol}, but searches for a global
+symbol with static linkage named @var{name} in this objfile.
+@end defun
+
@node Frames In Python
@subsubsection Accessing inferior stack frames from Python
should not assume that a specific block object will always contain a
given symbol, since changes in @value{GDBN} features and
infrastructure may cause symbols move across blocks in a symbol
-table.
+table. You can also use Python's @dfn{dictionary syntax} to access
+variables in this block, e.g.:
+
+@smallexample
+symbol = some_block['variable'] # symbol is of type gdb.Symbol
+@end smallexample
The following block-related functions are available in the @code{gdb}
module:
is not found.
@end defun
+@findex gdb.lookup_static_symbol
+@defun gdb.lookup_static_symbol (name @r{[}, domain@r{]})
+This function searches for a global symbol with static linkage by name.
+The search scope can be restricted to by the domain argument.
+
+@var{name} is the name of the symbol. It must be a string.
+The optional @var{domain} argument restricts the search to the domain type.
+The @var{domain} argument must be a domain constant defined in the @code{gdb}
+module and described later in this chapter.
+
+The result is a @code{gdb.Symbol} object or @code{None} if the symbol
+is not found.
+
+Note that this function will not find function-scoped static variables. To look
+up such variables, iterate over the variables of the function's
+@code{gdb.Block} and check that @code{block.addr_class} is
+@code{gdb.SYMBOL_LOC_STATIC}.
+
+There can be multiple global symbols with static linkage with the same
+name. This function will only return the first matching symbol that
+it finds. Which symbol is found depends on where @value{GDBN} is
+currently stopped, as @value{GDBN} will first search for matching
+symbols in the current object file, and then search all other object
+files. If the application is not yet running then @value{GDBN} will
+search all object files in the order they appear in the debug
+information.
+@end defun
+
+@findex gdb.lookup_static_symbols
+@defun gdb.lookup_static_symbols (name @r{[}, domain@r{]})
+Similar to @code{gdb.lookup_static_symbol}, this function searches for
+global symbols with static linkage by name, and optionally restricted
+by the domain argument. However, this function returns a list of all
+matching symbols found, not just the first one.
+
+@var{name} is the name of the symbol. It must be a string.
+The optional @var{domain} argument restricts the search to the domain type.
+The @var{domain} argument must be a domain constant defined in the @code{gdb}
+module and described later in this chapter.
+
+The result is a list of @code{gdb.Symbol} objects which could be empty
+if no matching symbols were found.
+
+Note that this function will not find function-scoped static variables. To look
+up such variables, iterate over the variables of the function's
+@code{gdb.Block} and check that @code{block.addr_class} is
+@code{gdb.SYMBOL_LOC_STATIC}.
+@end defun
+
A @code{gdb.Symbol} object has the following attributes:
@defvar Symbol.type
@end table
@end defun
+@node TUI Windows In Python
+@subsubsection Implementing new TUI windows
+@cindex Python TUI Windows
+
+New TUI (@pxref{TUI}) windows can be implemented in Python.
+
+@findex gdb.register_window_type
+@defun gdb.register_window_type (@var{name}, @var{factory})
+Because TUI windows are created and destroyed depending on the layout
+the user chooses, new window types are implemented by registering a
+factory function with @value{GDBN}.
+
+@var{name} is the name of the new window. It's an error to try to
+replace one of the built-in windows, but other window types can be
+replaced.
+
+@var{function} is a factory function that is called to create the TUI
+window. This is called with a single argument of type
+@code{gdb.TuiWindow}, described below. It should return an object
+that implements the TUI window protocol, also described below.
+@end defun
+
+As mentioned above, when a factory function is called, it is passed a
+an object of type @code{gdb.TuiWindow}. This object has these
+methods and attributes:
+
+@defun TuiWindow.is_valid ()
+This method returns @code{True} when this window is valid. When the
+user changes the TUI layout, windows no longer visible in the new
+layout will be destroyed. At this point, the @code{gdb.TuiWindow}
+will no longer be valid, and methods (and attributes) other than
+@code{is_valid} will throw an exception.
+@end defun
+
+@defvar TuiWindow.width
+This attribute holds the width of the window. It is not writable.
+@end defvar
+
+@defvar TuiWindow.height
+This attribute holds the height of the window. It is not writable.
+@end defvar
+
+@defvar TuiWindow.title
+This attribute holds the window's title, a string. This is normally
+displayed above the window. This attribute can be modified.
+@end defvar
+
+@defun TuiWindow.erase ()
+Remove all the contents of the window.
+@end defun
+
+@defun TuiWindow.write (@var{string})
+Write @var{string} to the window. @var{string} can contain ANSI
+terminal escape styling sequences; @value{GDBN} will translate these
+as appropriate for the terminal.
+@end defun
+
+The factory function that you supply should return an object
+conforming to the TUI window protocol. These are the method that can
+be called on this object, which is referred to below as the ``window
+object''. The methods documented below are optional; if the object
+does not implement one of these methods, @value{GDBN} will not attempt
+to call it. Additional new methods may be added to the window
+protocol in the future. @value{GDBN} guarantees that they will begin
+with a lower-case letter, so you can start implementation methods with
+upper-case letters or underscore to avoid any future conflicts.
+
+@defun Window.close ()
+When the TUI window is closed, the @code{gdb.TuiWindow} object will be
+put into an invalid state. At this time, @value{GDBN} will call
+@code{close} method on the window object.
+
+After this method is called, @value{GDBN} will discard any references
+it holds on this window object, and will no longer call methods on
+this object.
+@end defun
+
+@defun Window.render ()
+In some situations, a TUI window can change size. For example, this
+can happen if the user resizes the terminal, or changes the layout.
+When this happens, @value{GDBN} will call the @code{render} method on
+the window object.
+
+If your window is intended to update in response to changes in the
+inferior, you will probably also want to register event listeners and
+send output to the @code{gdb.TuiWindow}.
+@end defun
+
+@defun Window.hscroll (@var{num})
+This is a request to scroll the window horizontally. @var{num} is the
+amount by which to scroll, with negative numbers meaning to scroll
+right. In the TUI model, it is the viewport that moves, not the
+contents. A positive argument should cause the viewport to move
+right, and so the content should appear to move to the left.
+@end defun
+
+@defun Window.vscroll (@var{num})
+This is a request to scroll the window vertically. @var{num} is the
+amount by which to scroll, with negative numbers meaning to scroll
+backward. In the TUI model, it is the viewport that moves, not the
+contents. A positive argument should cause the viewport to move down,
+and so the content should appear to move up.
+@end defun
+
@node Python Auto-loading
@subsection Python Auto-loading
@cindex Python auto-loading
For example:
@smallexample
-substitute_prompt (``frame: \f,
- print arguments: \p@{print frame-arguments@}'')
+substitute_prompt ("frame: \f, args: \p@{print frame-arguments@}")
@end smallexample
@exdent will return the string:
@smallexample
-"frame: main, print arguments: scalars"
+"frame: main, args: scalars"
@end smallexample
@end table
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