the default, which is to read it incrementally as it is needed.
This makes startup slower, but makes future operations faster.
+@item --readnever
+@anchor{--readnever}
+@cindex @code{--readnever}, command-line option
+Do not read each symbol file's symbolic debug information. This makes
+startup faster but at the expense of not being able to perform
+symbolic debugging. DWARF unwind information is also not read,
+meaning backtraces may become incomplete or inaccurate. One use of
+this is when a user simply wants to do the following sequence: attach,
+dump core, detach. Loading the debugging information in this case is
+an unnecessary cause of delay.
@end table
@node Mode Options
Specifies the line that begins the body of the function @var{function}.
For example, in C, this is the line with the open brace.
+By default, in C@t{++} and Ada, @var{function} is interpreted as
+specifying all functions named @var{function} in all scopes. For
+C@t{++}, this means in all namespaces and classes. For Ada, this
+means in all packages.
+
+For example, assuming a program with C@t{++} symbols named
+@code{A::B::func} and @code{B::func}, both commands @w{@kbd{break
+func}} and @w{@kbd{break B::func}} set a breakpoint on both symbols.
+
+Commands that accept a linespec let you override this with the
+@code{-qualified} option. For example, @w{@kbd{break -qualified
+func}} sets a breakpoint on a free-function named @code{func} ignoring
+any C@t{++} class methods and namespace functions called @code{func}.
+
+@xref{Explicit Locations}.
+
@item @var{function}:@var{label}
Specifies the line where @var{label} appears in @var{function}.
or @code{-line}) refer to the line that begins the body of the function.
In C, for example, this is the line with the open brace.
+By default, in C@t{++} and Ada, @var{function} is interpreted as
+specifying all functions named @var{function} in all scopes. For
+C@t{++}, this means in all namespaces and classes. For Ada, this
+means in all packages.
+
+For example, assuming a program with C@t{++} symbols named
+@code{A::B::func} and @code{B::func}, both commands @w{@kbd{break
+-function func}} and @w{@kbd{break -function B::func}} set a
+breakpoint on both symbols.
+
+You can use the @kbd{-qualified} flag to override this (see below).
+
+@item -qualified
+
+This flag makes @value{GDBN} interpret a function name specified with
+@kbd{-function} as a complete fully-qualified name.
+
+For example, assuming a C@t{++} program with symbols named
+@code{A::B::func} and @code{B::func}, the @w{@kbd{break -qualified
+-function B::func}} command sets a breakpoint on @code{B::func}, only.
+
+(Note: the @kbd{-qualified} option can precede a linespec as well
+(@pxref{Linespec Locations}), so the particular example above could be
+simplified as @w{@kbd{break -qualified B::func}}.)
+
@item -label @var{label}
The value specifies the name of a label. When the function
name is not specified, the label is searched in the function of the currently
@end table
Explicit location options may be abbreviated by omitting any non-unique
-trailing characters from the option name, e.g., @code{break -s main.c -li 3}.
+trailing characters from the option name, e.g., @w{@kbd{break -s main.c -li 3}}.
@node Address Locations
@subsection Address Locations
All values are interpreted in the current language.
This means, for example, that if the current source language is C/C@t{++}
then searching for the string ``hello'' includes the trailing '\0'.
+The null terminator can be removed from searching by using casts,
+e.g.: @samp{@{char[5]@}"hello"}.
If the value size is not specified, it is taken from the
value's type in the current language.
(gdb) find &hello[0], +sizeof(hello), 'h', 'e', 'l', 'l', 'o'
0x8049567 <hello.1620>
0x804956d <hello.1620+6>
-2 patterns found
+2 patterns found.
+(gdb) find &hello[0], +sizeof(hello), @{char[5]@}"hello"
+0x8049567 <hello.1620>
+0x804956d <hello.1620+6>
+2 patterns found.
(gdb) find /b1 &hello[0], +sizeof(hello), 'h', 0x65, 'l'
0x8049567 <hello.1620>
1 pattern found
also use the @value{GDBN} command-line word completion facilities to list the
available choices, or to finish the type list for you.
@xref{Completion,, Command Completion}, for details on how to do this.
+
+@item @r{Breakpoints in functions with ABI tags}
+
+The GNU C@t{++} compiler introduced the notion of ABI ``tags'', which
+correspond to changes in the ABI of a type, function, or variable that
+would not otherwise be reflected in a mangled name. See
+@url{https://developers.redhat.com/blog/2015/02/05/gcc5-and-the-c11-abi/}
+for more detail.
+
+The ABI tags are visible in C@t{++} demangled names. For example, a
+function that returns a std::string:
+
+@smallexample
+std::string function(int);
+@end smallexample
+
+@noindent
+when compiled for the C++11 ABI is marked with the @code{cxx11} ABI
+tag, and @value{GDBN} displays the symbol like this:
+
+@smallexample
+function[abi:cxx11](int)
+@end smallexample
+
+You can set a breakpoint on such functions simply as if they had no
+tag. For example:
+
+@smallexample
+(gdb) b function(int)
+Breakpoint 2 at 0x40060d: file main.cc, line 10.
+(gdb) info breakpoints
+Num Type Disp Enb Address What
+1 breakpoint keep y 0x0040060d in function[abi:cxx11](int)
+ at main.cc:10
+@end smallexample
+
+On the rare occasion you need to disambiguate between different ABI
+tags, you can do so by simply including the ABI tag in the function
+name, like:
+
+@smallexample
+(@value{GDBP}) b ambiguous[abi:other_tag](int)
+@end smallexample
@end table
@node Decimal Floating Point
@item
Method calls cannot be made via traits.
-@item
-Trait objects cannot be created or inspected.
-
@item
Operator overloading is not implemented.
load symbol table information, if you want to be sure @value{GDBN} has the
entire symbol table available.
+@cindex @code{-readnever}, option for symbol-file command
+@cindex never read symbols
+@cindex symbols, never read
+@item symbol-file @r{[} -readnever @r{]} @var{filename}
+@itemx file @r{[} -readnever @r{]} @var{filename}
+You can instruct @value{GDBN} to never read the symbolic information
+contained in @var{filename} by using the @samp{-readnever} option.
+@xref{--readnever}.
+
@c FIXME: for now no mention of directories, since this seems to be in
@c flux. 13mar1992 status is that in theory GDB would look either in
@c current dir or in same dir as myprog; but issues like competing
@kindex add-symbol-file
@cindex dynamic linking
@item add-symbol-file @var{filename} @var{address}
-@itemx add-symbol-file @var{filename} @var{address} @r{[} -readnow @r{]}
+@itemx add-symbol-file @var{filename} @var{address} @r{[} -readnow @r{|} -readnever @r{]}
@itemx add-symbol-file @var{filename} @var{address} -s @var{section} @var{address} @dots{}
The @code{add-symbol-file} command reads additional symbol table
information from the file @var{filename}. You would use this command
Whenever a @code{*stopped} record is emitted because the program
stopped after hitting an exception catchpoint (@pxref{Set Catchpoints}),
@value{GDBN} provides the name of the exception that was raised via
-the @code{exception-name} field.
+the @code{exception-name} field. Also, for exceptions that were raised
+with an exception message, @value{GDBN} provides that message via
+the @code{exception-message} field.
@c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@node GDB/MI Simple Examples
projects / deliverable / binutils-gdb.git / blobdiff