## GIFunctionInfo

GIFunctionInfo — Struct representing a function

## Synopsis

    #define             GI_IS_FUNCTION_INFO                 (info)
    typedef             GIFunctionInfo;
    enum                GInvokeError;
    enum                GIFunctionInfoFlags;
    #define             G_INVOKE_ERROR
    const gchar *            g_function_info_get_symbol     (GIFunctionInfo *info);
    GIFunctionInfoFlags  g_function_info_get_flags          (GIFunctionInfo *info);
    GIPropertyInfo *         g_function_info_get_property   (GIFunctionInfo *info);
    GIVFuncInfo *            g_function_info_get_vfunc      (GIFunctionInfo *info);
    gboolean            g_function_info_invoke              (GIFunctionInfo *info,
                                                             const GIArgument *in_args,
                                                             int n_in_args,
                                                             const GIArgument *out_args,
                                                             int n_out_args,
                                                             GIArgument *return_value,
                                                             GError **error);

## Description

GIFunctionInfo represents a function, method or constructor. To find out what kind of entity a GIFunctionInfo represents, call `g_function_info_get_flags()`.

See also GICallableInfo for information on how to retreive arguments and other metadata.

## Struct hierarchy

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

## Details

### GI_IS_FUNCTION_INFO()

    #define             GI_IS_FUNCTION_INFO(info)

### GIFunctionInfo

    typedef GIBaseInfo GIFunctionInfo;

Represents a function, eg arguments and return value.

### enum GInvokeError

    typedef enum
    {
      G_INVOKE_ERROR_FAILED,
      G_INVOKE_ERROR_SYMBOL_NOT_FOUND,
      G_INVOKE_ERROR_ARGUMENT_MISMATCH
    } GInvokeError;

An error occuring while invoking a function via `g_function_info_invoke()`.

`G_INVOKE_ERROR_FAILED` | invokation failed, unknown error.
`G_INVOKE_ERROR_SYMBOL_NOT_FOUND` | symbol couldn't be found in any of the libraries associated with the typelib of the function.
`G_INVOKE_ERROR_ARGUMENT_MISMATCH` | the arguments provided didn't match the expected arguments for the functions type signature.

### enum GIFunctionInfoFlags

    typedef enum
    {
      GI_FUNCTION_IS_METHOD      = 1 << 0,
      GI_FUNCTION_IS_CONSTRUCTOR = 1 << 1,
      GI_FUNCTION_IS_GETTER      = 1 << 2,
      GI_FUNCTION_IS_SETTER      = 1 << 3,
      GI_FUNCTION_WRAPS_VFUNC    = 1 << 4,
      GI_FUNCTION_THROWS         = 1 << 5
    } GIFunctionInfoFlags;

Flags for a GIFunctionInfo struct.

`GI_FUNCTION_IS_METHOD` | is a method.
`GI_FUNCTION_IS_CONSTRUCTOR` | is a constructor.
`GI_FUNCTION_IS_GETTER` | is a getter of a GIPropertyInfo.
`GI_FUNCTION_IS_SETTER` | is a setter of a GIPropertyInfo.
`GI_FUNCTION_WRAPS_VFUNC` | represents a virtual function.
`GI_FUNCTION_THROWS` | the function may throw an error.

### G_INVOKE_ERROR

    #define G_INVOKE_ERROR (g_invoke_error_quark ())

### g_function_info_get_symbol ()

    const gchar *            g_function_info_get_symbol     (GIFunctionInfo *info);

Obtain the symbol of the function. The symbol is the name of the exported function, suitable to be used as an argument to `g_module_symbol()`.

`info` : | a GIFunctionInfo
Returns : | the symbol

### g_function_info_get_flags ()

    GIFunctionInfoFlags  g_function_info_get_flags          (GIFunctionInfo *info);

Obtain the GIFunctionInfoFlags for the `info`.

`info` : | a GIFunctionInfo
Returns : | the flags

### g_function_info_get_property ()

    GIPropertyInfo *         g_function_info_get_property   (GIFunctionInfo *info);

Obtain the property associated with this GIFunctionInfo. Only GIFunctionInfo with the flag `GI_FUNCTION_IS_GETTER` or `GI_FUNCTION_IS_SETTER` have a property set. For other cases, `NULL` will be returned.

`info` : | a GIFunctionInfo
Returns : | the property or `NULL` if not set. Free it with `g_base_info_unref()` when done. [transfer full]

### g_function_info_get_vfunc ()

    GIVFuncInfo *            g_function_info_get_vfunc      (GIFunctionInfo *info);

Obtain the virtual function associated with this GIFunctionInfo. Only GIFunctionInfo with the flag `GI_FUNCTION_WRAPS_VFUNC` has a virtual function set. For other cases, `NULL` will be returned.

`info` : | a GIFunctionInfo
Returns : | the virtual function or `NULL` if not set. Free it by calling `g_base_info_unref()` when done. [transfer full]

### g_function_info_invoke ()

    gboolean            g_function_info_invoke              (GIFunctionInfo *info,
                                                             const GIArgument *in_args,
                                                             int n_in_args,
                                                             const GIArgument *out_args,
                                                             int n_out_args,
                                                             GIArgument *return_value,
                                                             GError **error);

Invokes the function described in `info` with the given arguments. Note that inout parameters must appear in both argument lists. This function uses `dlsym()` to obtain a pointer to the function, so the library or shared object containing the described function must either be linked to the caller, or must have been `g_module_symbol()`ed before calling this function.

`info` : | a GIFunctionInfo describing the function to invoke
`in_args` : | an array of GIArguments, one for each in parameter of `info`. If there are no in parameter, `in_args` can be `NULL`
`n_in_args` : | the length of the `in_args` array
`out_args` : | an array of GIArguments, one for each out parameter of `info`. If there are no out parameters, `out_args` may be `NULL`
`n_out_args` : | the length of the `out_args` array
`return_value` : | return location for the return value of the function. If the function returns void, `return_value` may be `NULL`
`error` : | return location for detailed error information, or `NULL`
Returns : | `TRUE` if the function has been invoked, `FALSE` if an error occurred.