GICallableInfo: GObject Introspection Reference Manual

## GICallableInfo GICallableInfo — Struct representing a callable |

## Functions

#define | GI_IS_CALLABLE_INFO()
gboolean | g_callable_info_can_throw_gerror ()
gint | g_callable_info_get_n_args ()
GIArgInfo * | g_callable_info_get_arg ()
GITransfer | g_callable_info_get_caller_owns ()
const gchar * | g_callable_info_get_return_attribute ()
GITypeInfo * | g_callable_info_get_return_type ()
gboolean | g_callable_info_invoke ()
gboolean | g_callable_info_is_method ()
gboolean | g_callable_info_iterate_return_attributes ()
void | g_callable_info_load_arg ()
void | g_callable_info_load_return_type ()
gboolean | g_callable_info_may_return_null ()
gboolean | g_callable_info_skip_return ()

## Types and Values

typedef | GICallableInfo

## Description

GICallableInfo represents an entity which is callable. Currently a function (GIFunctionInfo), virtual function, (GIVFuncInfo) or callback (GICallbackInfo).

A callable has a list of arguments (GIArgInfo), a return type, direction and a flag which decides if it returns null.

## Struct hierarchy

      GIBaseInfo
       +----GICallableInfo
             +----GIFunctionInfo
             +----GISignalInfo
             +----GIVFuncInfo

## Functions

### GI_IS_CALLABLE_INFO()

    #define             GI_IS_CALLABLE_INFO(info)

Checks if `info` is a GICallableInfo or derived from it.

#### Parameters

info | an info structure |

### g_callable_info_can_throw_gerror ()

    gboolean
    g_callable_info_can_throw_gerror (GICallableInfo *info);

TODO

#### Parameters

info | a GICallableInfo |

#### Returns

`TRUE` if this GICallableInfo can throw a GError

Since: 1.34

### g_callable_info_get_n_args ()

    gint
    g_callable_info_get_n_args (GICallableInfo *info);

Obtain the number of arguments (both IN and OUT) for this callable.

#### Parameters

info | a GICallableInfo |

#### Returns

The number of arguments this callable expects.

### g_callable_info_get_arg ()

    GIArgInfo *
    g_callable_info_get_arg (GICallableInfo *info,
                             gint n);

Obtain information about a particular argument of this callable.

#### Parameters

info | a GICallableInfo |
n | the argument index to fetch |

#### Returns

the GIArgInfo. Free it with `g_base_info_unref()` when done.

[transfer full]

### g_callable_info_get_caller_owns ()

    GITransfer
    g_callable_info_get_caller_owns (GICallableInfo *info);

See whether the caller owns the return value of this callable. GITransfer contains a list of possible transfer values.

#### Parameters

info | a GICallableInfo |

#### Returns

the transfer mode for the return value of the callable

### g_callable_info_get_return_attribute ()

    const gchar *
    g_callable_info_get_return_attribute (GICallableInfo *info,
                                          const gchar *name);

Retrieve an arbitrary attribute associated with the return value.

#### Parameters

info | a GICallableInfo |
name | a freeform string naming an attribute |

#### Returns

The value of the attribute, or `NULL` if no such attribute exists

### g_callable_info_get_return_type ()

    GITypeInfo *
    g_callable_info_get_return_type (GICallableInfo *info);

Obtain the return type of a callable item as a GITypeInfo.

#### Parameters

info | a GICallableInfo |

#### Returns

the GITypeInfo. Free the struct by calling `g_base_info_unref()` when done.

[transfer full]

### g_callable_info_invoke ()

    gboolean
    g_callable_info_invoke (GICallableInfo *info,
                            gpointer function,
                            const GIArgument *in_args,
                            int n_in_args,
                            const GIArgument *out_args,
                            int n_out_args,
                            GIArgument *return_value,
                            gboolean is_method,
                            gboolean throws,
                            GError **error);

TODO

#### Parameters

info | TODO |
function | TODO |
in_args | TODO. | [array length=n_in_args]
n_in_args | TODO |
out_args | TODO. | [array length=n_out_args]
n_out_args | TODO |
return_value | TODO |
is_method | TODO |
throws | TODO |
error | TODO |

### g_callable_info_is_method ()

    gboolean
    g_callable_info_is_method (GICallableInfo *info);

Determines if the callable info is a method. For GIVFuncInfos, GICallbackInfos, and GISignalInfos, this is always true. Otherwise, this looks at the `GI_FUNCTION_IS_METHOD` flag on the GIFunctionInfo.

Concretely, this function returns whether `g_callable_info_get_n_args()` matches the number of arguments in the raw C method. For methods, there is one more C argument than is exposed by introspection: the "self" or "this" object.

#### Parameters

info | a GICallableInfo |

#### Returns

`TRUE` if `info` is a method, `FALSE` otherwise

Since: 1.34

### g_callable_info_iterate_return_attributes ()

    gboolean
    g_callable_info_iterate_return_attributes
                                   (GICallableInfo *info,
                                    GIAttributeIter *iterator,
                                    char **name,
                                    char **value);

Iterate over all attributes associated with the return value. The iterator structure is typically stack allocated, and must have its first member initialized to `NULL`.

Both the `name` and `value` should be treated as constants and must not be freed.

See `g_base_info_iterate_attributes()` for an example of how to use a similar API.

#### Parameters

info | a GICallableInfo |
iterator | a GIAttributeIter structure, must be initialized; see below. | [inout]
name | Returned name, must not be freed. | [out][transfer none]
value | Returned name, must not be freed. | [out][transfer none]

#### Returns

`TRUE` if there are more attributes

### g_callable_info_load_arg ()

    void
    g_callable_info_load_arg (GICallableInfo *info,
                              gint n,
                              GIArgInfo *arg);

Obtain information about a particular argument of this callable; this function is a variant of `g_callable_info_get_arg()` designed for stack allocation.

The initialized `arg` must not be referenced after `info` is deallocated.

#### Parameters

info | a GICallableInfo |
n | the argument index to fetch |
arg | Initialize with argument number `n` . | [out caller-allocates]

### g_callable_info_load_return_type ()

    void
    g_callable_info_load_return_type (GICallableInfo *info,
                                      GITypeInfo *type);

Obtain information about a return value of callable; this function is a variant of `g_callable_info_get_return_type()` designed for stack allocation.

The initialized `type` must not be referenced after `info` is deallocated.

#### Parameters

info | a GICallableInfo |
type | Initialized with return type of `info` . | [out caller-allocates]

### g_callable_info_may_return_null ()

    gboolean
    g_callable_info_may_return_null (GICallableInfo *info);

See if a callable could return `NULL`.

#### Parameters

info | a GICallableInfo |

#### Returns

`TRUE` if callable could return `NULL`

### g_callable_info_skip_return ()

    gboolean
    g_callable_info_skip_return (GICallableInfo *info);

See if a callable's return value is only useful in C.

#### Parameters

info | a GICallableInfo |

#### Returns

`TRUE` if return value is only useful in C.

## Types and Values

### GICallableInfo

Represents a callable, either GIFunctionInfo, GICallbackInfo or GIVFuncInfo.