your program. @xref{Environment, ,Your Program's Environment}.
@item The @emph{working directory.}
-Your program inherits its working directory from @value{GDBN}. You can set
-the @value{GDBN} working directory with the @code{cd} command in @value{GDBN}.
+You can set your program's working directory with the command
+@kbd{set cwd}. If you do not set any working directory with this
+command, your program will inherit @value{GDBN}'s working directory.
@xref{Working Directory, ,Your Program's Working Directory}.
@item The @emph{standard input and output.}
@samp{start} or @samp{run}.
It is sometimes necessary to debug the program during elaboration. In
-these cases, using the @code{start} command would stop the execution of
-your program too late, as the program would have already completed the
-elaboration phase. Under these circumstances, insert breakpoints in your
-elaboration code before running your program.
+these cases, using the @code{start} command would stop the execution
+of your program too late, as the program would have already completed
+the elaboration phase. Under these circumstances, either insert
+breakpoints in your elaboration code before running your program or
+use the @code{starti} command.
+
+@kindex starti
+@item starti
+@cindex run to first instruction
+The @samp{starti} command does the equivalent of setting a temporary
+breakpoint at the first instruction of a program's execution and then
+invoking the @samp{run} command. For programs containing an
+elaboration phase, the @code{starti} command will stop execution at
+the start of the elaboration phase.
@anchor{set exec-wrapper}
@kindex set exec-wrapper
@section Your Program's Working Directory
@cindex working directory (of your program)
-Each time you start your program with @code{run}, it inherits its
-working directory from the current working directory of @value{GDBN}.
-The @value{GDBN} working directory is initially whatever it inherited
-from its parent process (typically the shell), but you can specify a new
-working directory in @value{GDBN} with the @code{cd} command.
-
-The @value{GDBN} working directory also serves as a default for the commands
-that specify files for @value{GDBN} to operate on. @xref{Files, ,Commands to
-Specify Files}.
+Each time you start your program with @code{run}, the inferior will be
+initialized with the current working directory specified by the
+@kbd{set cwd} command. If no directory has been specified by this
+command, then the inferior will inherit @value{GDBN}'s current working
+directory as its working directory.
+
+@table @code
+@kindex set cwd
+@cindex change inferior's working directory
+@anchor{set cwd command}
+@item set cwd @r{[}@var{directory}@r{]}
+Set the inferior's working directory to @var{directory}, which will be
+@code{glob}-expanded in order to resolve tildes (@file{~}). If no
+argument has been specified, the command clears the setting and resets
+it to an empty state. This setting has no effect on @value{GDBN}'s
+working directory, and it only takes effect the next time you start
+the inferior. The @file{~} in @var{directory} is a short for the
+@dfn{home directory}, usually pointed to by the @env{HOME} environment
+variable. On MS-Windows, if @env{HOME} is not defined, @value{GDBN}
+uses the concatenation of @env{HOMEDRIVE} and @env{HOMEPATH} as
+fallback.
+
+You can also change @value{GDBN}'s current working directory by using
+the @code{cd} command.
+@xref{cd command}
+
+@kindex show cwd
+@cindex show inferior's working directory
+@item show cwd
+Show the inferior's working directory. If no directory has been
+specified by @kbd{set cwd}, then the default inferior's working
+directory is the same as @value{GDBN}'s working directory.
-@table @code
@kindex cd
-@cindex change working directory
+@cindex change @value{GDBN}'s working directory
+@anchor{cd command}
@item cd @r{[}@var{directory}@r{]}
Set the @value{GDBN} working directory to @var{directory}. If not
given, @var{directory} uses @file{'~'}.
+The @value{GDBN} working directory serves as a default for the
+commands that specify files for @value{GDBN} to operate on.
+@xref{Files, ,Commands to Specify Files}.
+@xref{set cwd command}
+
@kindex pwd
@item pwd
Print the @value{GDBN} working directory.
by the debug information, @value{GDBN} will say @samp{<incomplete
type>}. @xref{Symbols, incomplete type}, for more about this.
+@cindex no debug info variables
+If you try to examine or use the value of a (global) variable for
+which @value{GDBN} has no type information, e.g., because the program
+includes no debug information, @value{GDBN} displays an error message.
+@xref{Symbols, unknown type}, for more about unknown types. If you
+cast the variable to its declared type, @value{GDBN} gets the
+variable's value using the cast-to type as the variable's type. For
+example, in a C program:
+
+@smallexample
+ (@value{GDBP}) p var
+ 'var' has unknown type; cast it to its declared type
+ (@value{GDBP}) p (float) var
+ $1 = 3.14
+@end smallexample
+
If you append @kbd{@@entry} string to a function parameter name you get its
value at the time the function got called. If the value is not available an
error message is printed. Entry values are available only with some compilers.
``Incomplete type'' is C terminology for data types that are not
completely specified.
+@cindex unknown type
+Othertimes, information about a variable's type is completely absent
+from the debug information included in the program. This most often
+happens when the program or library where the variable is defined
+includes no debug information at all. @value{GDBN} knows the variable
+exists from inspecting the linker/loader symbol table (e.g., the ELF
+dynamic symbol table), but such symbols do not contain type
+information. Inspecting the type of a (global) variable for which
+@value{GDBN} has no type information shows:
+
+@smallexample
+ (@value{GDBP}) ptype var
+ type = <data variable, no debug info>
+@end smallexample
+
+@xref{Variables, no debug info variables}, for how to print the values
+of such variables.
+
@kindex info types
@item info types @var{regexp}
@itemx info types
@end table
-@cindex weak alias functions
-Sometimes, a function you wish to call is actually a @dfn{weak alias}
-for another function. In such case, @value{GDBN} might not pick up
-the type information, including the types of the function arguments,
-which causes @value{GDBN} to call the inferior function incorrectly.
-As a result, the called function will function erroneously and may
-even crash. A solution to that is to use the name of the aliased
-function instead.
+@subsection Calling functions with no debug info
+
+@cindex no debug info functions
+Sometimes, a function you wish to call is missing debug information.
+In such case, @value{GDBN} does not know the type of the function,
+including the types of the function's parameters. To avoid calling
+the inferior function incorrectly, which could result in the called
+function functioning erroneously and even crash, @value{GDBN} refuses
+to call the function unless you tell it the type of the function.
+
+For prototyped (i.e.@: ANSI/ISO style) functions, there are two ways
+to do that. The simplest is to cast the call to the function's
+declared return type. For example:
+
+@smallexample
+(@value{GDBP}) p getenv ("PATH")
+'getenv' has unknown return type; cast the call to its declared return type
+(@value{GDBP}) p (char *) getenv ("PATH")
+$1 = 0x7fffffffe7ba "/usr/local/bin:/"...
+@end smallexample
+
+Casting the return type of a no-debug function is equivalent to
+casting the function to a pointer to a prototyped function that has a
+prototype that matches the types of the passed-in arguments, and
+calling that. I.e., the call above is equivalent to:
+
+@smallexample
+(@value{GDBP}) p ((char * (*) (const char *)) getenv) ("PATH")
+@end smallexample
+
+@noindent
+and given this prototyped C or C++ function with float parameters:
+
+@smallexample
+float multiply (float v1, float v2) @{ return v1 * v2; @}
+@end smallexample
+
+@noindent
+these calls are equivalent:
+
+@smallexample
+(@value{GDBP}) p (float) multiply (2.0f, 3.0f)
+(@value{GDBP}) p ((float (*) (float, float)) multiply) (2.0f, 3.0f)
+@end smallexample
+
+If the function you wish to call is declared as unprototyped (i.e.@:
+old K&R style), you must use the cast-to-function-pointer syntax, so
+that @value{GDBN} knows that it needs to apply default argument
+promotions (promote float arguments to double). @xref{ABI, float
+promotion}. For example, given this unprototyped C function with
+float parameters, and no debug info:
+
+@smallexample
+float
+multiply_noproto (v1, v2)
+ float v1, v2;
+@{
+ return v1 * v2;
+@}
+@end smallexample
+
+@noindent
+you call it like this:
+
+@smallexample
+ (@value{GDBP}) p ((float (*) ()) multiply_noproto) (2.0f, 3.0f)
+@end smallexample
@node Patching
@section Patching Programs
@smallexample
(@value{GDBP}) print 'cygwin1!__argv'
-$1 = 268572168
+'cygwin1!__argv' has unknown type; cast it to its declared type
@end smallexample
@smallexample
(@value{GDBP}) x 'cygwin1!__argv'
-0x10021610: "\230y\""
+'cygwin1!__argv' has unknown type; cast it to its declared type
@end smallexample
And two possible solutions:
@kindex maint selftest
@cindex self tests
+@item maint selftest @r{[}@var{filter}@r{]}
Run any self tests that were compiled in to @value{GDBN}. This will
print a message showing how many tests were run, and how many failed.
+If a @var{filter} is passed, only the tests with @var{filter} in their
+name will by ran.
+
+@kindex "maint info selftests"
+@cindex self tests
+@item maint info selftests
+List the selftests compiled in to @value{GDBN}.
@kindex maint set dwarf always-disassemble
@kindex maint show dwarf always-disassemble
the thread was last executing on. The @samp{name} attribute, if
present, specifies the human-readable name of the thread. The content
of the of @samp{thread} element is interpreted as human-readable
-auxiliary information.
+auxiliary information. The @samp{handle} attribute, if present,
+is a hex encoded representation of the thread handle.
+
@node Traceframe Info Format
@section Traceframe Info Format
contain the 128-bit wide vector registers @samp{v16} through
@samp{v31}.
+The @samp{org.gnu.gdb.s390.gs} feature is optional. It should contain
+the 64-bit wide guarded-storage-control registers @samp{gsd},
+@samp{gssm}, and @samp{gsepla}.
+
+The @samp{org.gnu.gdb.s390.gsbc} feature is optional. It should contain
+the 64-bit wide guarded-storage broadcast control registers
+@samp{bc_gsd}, @samp{bc_gssm}, and @samp{bc_gsepla}.
+
@node Sparc Features
@subsection Sparc Features
@cindex target descriptions, sparc32 features
projects / deliverable / binutils-gdb.git / blobdiff