GLib.clear_pointer (original) (raw)

Function

GLibclear_pointer

since: 2.34

Declaration [src]

void
g_clear_pointer (
  gpointer* pp,
  GDestroyNotify destroy
)

Description [src]

Clears a reference to a variable.

pp must not be NULL.

If the reference is NULL then this function does nothing. Otherwise, the variable is destroyed using destroy and the pointer is set to NULL.

A macro is also included that allows this function to be used without pointer casts. This will mask any warnings about incompatible function types or calling conventions, so you must ensure that your destroy function is compatible with being called as GDestroyNotify using the standard calling convention for the platform that GLib was compiled for; otherwise the program will experience undefined behaviour.

Examples of this kind of undefined behaviour include using many Windows Win32 APIs, as well as many if not all OpenGL and Vulkan calls on 32-bit Windows, which typically use the __stdcall calling convention rather than the__cdecl calling convention.

The affected functions can be used by wrapping them in aGDestroyNotify that is declared with the standard calling convention:

`// Wrapper needed to avoid mismatched calling conventions on Windows static void destroy_sync (void *sync) { glDeleteSync (sync); }

// …

g_clear_pointer (&sync, destroy_sync); `

Available since: 2.34

This function is not directly available to language bindings.

Parameters

pp

Type: gpointer*

A pointer to a variable, struct member etc. holding a pointer.

The argument will be modified by the function.

destroy

Type: GDestroyNotify

A function to which a gpointer can be passed, to destroy *pp.