Gdb/Types-In-Guile
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23.3.3.7 Types In Guile
GDB represents types from the inferior in objects of type
<gdb:type>
.
The following type-related procedures are provided by the
(gdb)
module.
- Scheme Procedure
- type? object
- Return
#t
ifobject
is an object of type<gdb:type>
. Otherwise return#f
.
- Scheme Procedure: lookup-type name [#:block block]
This function looks up a type by its
name
, which must be a string.If
block
is given, it is an object of type<gdb:block>
, andname
is looked up in that scope. Otherwise, it is searched for globally.Ordinarily, this function will return an instance of
<gdb:type>
. If the named type cannot be found, it will throw an exception.
- Scheme Procedure
- type-code type
- Return the type code of
type
. The type code will be one of theTYPE_CODE_
constants defined below.
- Scheme Procedure
- type-tag type
- Return the tag name of
type
. The tag name is the name afterstruct
,union
, orenum
in C and C++
; not all languages have this concept. If this type has no tag name, then#f
is returned.
- Scheme Procedure
- type-name type
- Return the name of
type
. If this type has no name, then#f
is returned.
- Scheme Procedure
- type-print-name type
- Return the print name of
type
. This returns something even for anonymous types. For example, for an anonymous C struct"struct {...}"
is returned.
- Scheme Procedure
- type-sizeof type
- Return the size of this type, in target
char
units. Usually, a target’schar
type will be an 8-bit byte. However, on some unusual platforms, this type may have a different size.
- Scheme Procedure
- type-strip-typedefs type
- Return a new
<gdb:type>
that represents the real type oftype
, after removing all layers of typedefs.
- Scheme Procedure
- type-array type n1 [n2]
- Return a new
<gdb:type>
object which represents an array of this type. If one argument is given, it is the inclusive upper bound of the array; in this case the lower bound is zero. If two arguments are given, the first argument is the lower bound of the array, and the second argument is the upper bound of the array. An array’s length must not be negative, but the bounds can be.
- Scheme Procedure: type-vector type n1 [n2]
Return a new
<gdb:type>
object which represents a vector of this type. If one argument is given, it is the inclusive upper bound of the vector; in this case the lower bound is zero. If two arguments are given, the first argument is the lower bound of the vector, and the second argument is the upper bound of the vector. A vector’s length must not be negative, but the bounds can be.The difference between an
array
and avector
is that arrays behave like in C: when used in expressions they decay to a pointer to the first element whereas vectors are treated as first class values.
- Scheme Procedure
- type-pointer type
- Return a new
<gdb:type>
object which represents a pointer totype
.
- Scheme Procedure
- type-range type
- Return a list of two elements: the low bound and high bound of
type
. Iftype
does not have a range, an exception is thrown.
- Scheme Procedure
- type-reference type
- Return a new
<gdb:type>
object which represents a reference totype
.
- Scheme Procedure: type-target type
Return a new
<gdb:type>
object which represents the target type oftype
.For a pointer type, the target type is the type of the pointed-to object. For an array type (meaning C-like arrays), the target type is the type of the elements of the array. For a function or method type, the target type is the type of the return value. For a complex type, the target type is the type of the elements. For a typedef, the target type is the aliased type.
If the type does not have a target, this method will throw an exception.
- Scheme Procedure
- type-const type
- Return a new
<gdb:type>
object which represents aconst
-qualified variant oftype
.
- Scheme Procedure
- type-volatile type
- Return a new
<gdb:type>
object which represents avolatile
-qualified variant oftype
.
- Scheme Procedure
- type-unqualified type
- Return a new
<gdb:type>
object which represents an unqualified variant oftype
. That is, the result is neitherconst
norvolatile
.
- Scheme Procedure
- type-num-fields
- Return the number of fields of
<gdb:type>
type
.
- Scheme Procedure
- type-fields type
- Return the fields of
type
as a list. For structure and union types,fields
has the usual meaning. Range types have two fields, the minimum and maximum values. Enum types have one field per enum constant. Function and method types have one field per parameter. The base types of C++
classes are also represented as fields. If the type has no fields, or does not fit into one of these categories, an empty list will be returned. See Fields of a type in Guile.
- Scheme Procedure
- make-field-iterator type
- Return the fields of
type
as a <gdb:iterator> object. See Iterators In Guile.
- Scheme Procedure: type-field type field-name
Return field named
field-name
intype
. The result is an object of type<gdb:field>
. See Fields of a type in Guile. If the type does not have fields, orfield-name
is not a field oftype
, an exception is thrown.For example, if
some-type
is a<gdb:type>
instance holding a structure type, you can access itsfoo
field with:(define bar (type-field some-type "foo"))
bar
will be a<gdb:field>
object.
- Scheme Procedure
- type-has-field? type name
- Return
#t
if<gdb:type>
type
has field namedname
. Otherwise return#f
.
Each type has a code, which indicates what category this type falls
into. The available type categories are represented by constants
defined in the (gdb)
module:
TYPE_CODE_PTR
- The type is a pointer.
TYPE_CODE_ARRAY
- The type is an array.
TYPE_CODE_STRUCT
- The type is a structure.
TYPE_CODE_UNION
- The type is a union.
TYPE_CODE_ENUM
- The type is an enum.
TYPE_CODE_FLAGS
- A bit flags type, used for things such as status registers.
TYPE_CODE_FUNC
- The type is a function.
TYPE_CODE_INT
- The type is an integer type.
TYPE_CODE_FLT
- A floating point type.
TYPE_CODE_VOID
- The special type
void
. TYPE_CODE_SET
- A Pascal set type.
TYPE_CODE_RANGE
- A range type, that is, an integer type with bounds.
TYPE_CODE_STRING
- A string type. Note that this is only used for certain languages with language-defined string types; C strings are not represented this way.
TYPE_CODE_BITSTRING
- A string of bits. It is deprecated.
TYPE_CODE_ERROR
- An unknown or erroneous type.
TYPE_CODE_METHOD
- A method type, as found in C
++
. TYPE_CODE_METHODPTR
- A pointer-to-member-function.
TYPE_CODE_MEMBERPTR
- A pointer-to-member.
TYPE_CODE_REF
- A reference type.
TYPE_CODE_CHAR
- A character type.
TYPE_CODE_BOOL
- A boolean type.
TYPE_CODE_COMPLEX
- A complex float type.
TYPE_CODE_TYPEDEF
- A typedef to some other type.
TYPE_CODE_NAMESPACE
- A C
++
namespace. TYPE_CODE_DECFLOAT
- A decimal floating point type.
TYPE_CODE_INTERNAL_FUNCTION
- A function internal to GDB. This is the type used to represent convenience functions (see Convenience Funs).
Further support for types is provided in the (gdb types)
Guile module (see Guile Types Module).
Each field is represented as an object of type <gdb:field>
.
The following field-related procedures are provided by the
(gdb)
module:
- Scheme Procedure
- field? object
- Return
#t
ifobject
is an object of type<gdb:field>
. Otherwise return#f
.
- Scheme Procedure
- field-name field
- Return the name of the field, or
#f
for anonymous fields.
- Scheme Procedure
- field-type field
- Return the type of the field. This is usually an instance of
<gdb:type>
, but it can be#f
in some situations.
- Scheme Procedure
- field-enumval field
- Return the enum value represented by
<gdb:field>
field
.
- Scheme Procedure
- field-bitpos field
- Return the bit position of
<gdb:field>
field
. This attribute is not available forstatic
fields (as in C++
).
- Scheme Procedure
- field-bitsize field
- If the field is packed, or is a bitfield, return the size of
<gdb:field>
field
in bits. Otherwise, zero is returned; in which case the field’s size is given by its type.
- Scheme Procedure
- field-artificial? field
- Return
#t
if the field is artificial, usually meaning that it was provided by the compiler and not the user. Otherwise return#f
.
- Scheme Procedure
- field-base-class? field
- Return
#t
if the field represents a base class of a C++
structure. Otherwise return#f
.
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