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Arg Info ¶

G-Golf Arg Info low level API.
GIArgInfo — Struct representing an argument.

Procedures ¶

g-arg-info-get-closure

g-arg-info-get-destroy

g-arg-info-get-direction

g-arg-info-get-ownership-transfer

g-arg-info-get-scope

g-arg-info-get-type

g-arg-info-may-be-null

g-arg-info-is-caller-allocates

g-arg-info-is-optional

g-arg-info-is-return-value

g-arg-info-is-skip

Types and Values ¶

%gi-direction

%gi-scope-type

%gi-transfer

Struct Hierarchy ¶

GIBaseInfo
  +— GIArgInfo

Description ¶

GIArgInfo represents an argument. An argument is always part of a GICallableInfo.

Procedures ¶

Note: in this section, the info argument is [must be] a pointer to a GIArgInfo.

Procedure: g-arg-info-get-closure info ¶

Returns the index of the user data argument or -1 if there is none.

Obtains the index of the user data argument. This is only valid for arguments which are callbacks.

Procedure: g-arg-info-get-destroy info ¶

Returns the index of the GDestroyNotify argument or -1 if there is none.

Obtains the index of the GDestroyNotify argument. This is only valid for arguments which are callbacks.

Procedure: g-arg-info-get-direction info ¶

Returns a symbol.

Obtains and returns the %gi-direction of the argument.

Procedure: g-arg-info-get-ownership-transfer info ¶

Returns a symbol.

Obtains and returns the %gi-transfer for this argument.

Procedure: g-arg-info-get-scope info ¶

Returns a symbol.

Obtains and returns the %gi-scope-type for this argument. The scope type explains how a callback is going to be invoked, most importantly when the resources required to invoke it can be freed.

Procedure: g-arg-info-get-type info ¶

Returns a pointer.

Obtains the GITypeInfo holding the type information for info. Free it using g-base-info-unref when done.

Procedure: g-arg-info-may-be-null info ¶

Returns #t or #f.

Obtains if the type of the argument includes the possibility of NULL. For ’in’ values this means that NULL is a valid value. For ’out’ values, this means that NULL may be returned.

Procedure: g-arg-info-is-caller-allocates info ¶

Returns #t or #f.

Obtain if the argument is a pointer to a struct or object that will receive an output of a function. The default assumption for out arguments which have allocation is that the callee allocates; if this is TRUE, then the caller must allocate.

Procedure: g-arg-info-is-optional info ¶

Returns #t or #f.

Obtains if the argument is optional. For ’out’ arguments this means that you can pass NULL in order to ignore the result.

Procedure: g-arg-info-is-return-value info ¶

Returns #t or #f.

Obtains if the argument is a retur value. It can either be a parameter or a return value.

Procedure: g-arg-info-is-skip info ¶

Returns #t or #f.

Obtains if an argument is only useful in C.

Types and Values ¶

Instance Variable of <gi-enum>: %gi-direction ¶

An instance of <gi-enum>, who’s members are the scheme representation of the direction of a GIArgInfo:

g-name: GIDirection
name: gi-direction
enum-set:

in

in argument.

out

out argument.

inout

in and out argument.

Instance Variable of <gi-enum>: %gi-scope-type ¶

An instance of <gi-enum>, who’s members are the scheme representation of the scope of a GIArgInfo. Scope type of a GIArgInfo representing callback, determines how the callback is invoked and is used to decide when the invoke structs can be freed.

g-name: GIScopeType
name: gi-scope-type
enum-set:

invalid

The argument is not of callback type.

call

The callback and associated user_data is only used during the call to this function.

async

The callback and associated user_data is only used until the callback is invoked, and the callback. is invoked always exactly once.

notified

The callback and and associated user_data is used until the caller is notfied via the destroy_notify.

Instance Variable of <gi-enum>: %gi-transfer ¶

The transfer is the exchange of data between two parts, from the callee to the caller. The callee is either a function/method/signal or an object/interface where a property is defined. The caller is the side accessing a property or calling a function. GITransfer specifies who’s responsible for freeing the resources after the ownership transfer is complete. In case of a containing type such as a list, an array or a hash table the container itself is specified differently from the items within the container itself. Each container is freed differently, check the documentation for the types themselves for information on how to free them.

An instance of <gi-enum>, who’s members are the scheme representation of the GITransfer:

g-name: GITransfer
name: gi-transfer
enum-set:

nothing

transfer nothing from the callee (function or the type instance the property belongs to) to the caller. The callee retains the ownership of the transfer and the caller doesn’t need to do anything to free up the resources of this transfer

container

transfer the container (list, array, hash table) from the callee to the caller. The callee retains the ownership of the individual items in the container and the caller has to free up the container resources g_list_free, g_hash_table_destroy, … of this transfer

everything

transfer everything, eg the container and its contents from the callee to the caller. This is the case when the callee creates a copy of all the data it returns. The caller is responsible for cleaning up the container and item resources of this transfer