gdb: Types In Guile
23.3.3.7 Types In Guile
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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' if OBJECT 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>', and NAME
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 the
'TYPE_CODE_' constants defined below.
-- Scheme Procedure: type-tag type
Return the tag name of TYPE. The tag name is the name after
'struct', 'union', or 'enum' 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's 'char' 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 of TYPE,
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 a 'vector' 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 to
TYPE.
-- Scheme Procedure: type-range type
Return a list of two elements: the low bound and high bound of
TYPE. If TYPE does not have a range, an exception is thrown.
-- Scheme Procedure: type-reference type
Return a new '<gdb:type>' object which represents a reference to
TYPE.
-- Scheme Procedure: type-target type
Return a new '<gdb:type>' object which represents the target type
of TYPE.
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 a
'const'-qualified variant of TYPE.
-- Scheme Procedure: type-volatile type
Return a new '<gdb:type>' object which represents a
'volatile'-qualified variant of TYPE.
-- Scheme Procedure: type-unqualified type
Return a new '<gdb:type>' object which represents an unqualified
variant of TYPE. That is, the result is neither 'const' nor
'volatile'.
-- 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. 
Fields of
a type in Guile.
-- Scheme Procedure: make-field-iterator type
Return the fields of TYPE as a <gdb:iterator> object.
Iterators In Guile.
-- Scheme Procedure: type-field type field-name
Return field named FIELD-NAME in TYPE. The result is an object of
type '<gdb:field>'. Fields of a type in Guile. If the
type does not have fields, or FIELD-NAME is not a field of TYPE, an
exception is thrown.
For example, if 'some-type' is a '<gdb:type>' instance holding a
structure type, you can access its 'foo' 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 named NAME. 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 (Convenience Funs).
Further support for types is provided in the '(gdb types)' Guile
module (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' if OBJECT 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 for 'static' 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'.
Info Catalog
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