Optional Functions

Macros
#define	APR_OPTIONAL_FN_TYPE(name)   apr_OFN_##name##_t
#define	APR_DECLARE_OPTIONAL_FN(ret, name, args)   typedef ret (APR_OPTIONAL_FN_TYPE(name)) args
#define	APR_REGISTER_OPTIONAL_FN(name)
#define	APR_RETRIEVE_OPTIONAL_FN(name)    (APR_OPTIONAL_FN_TYPE(name) *)apr_dynamic_fn_retrieve(#name)

Typedefs
typedef void()	apr_opt_fn_t(void)

Functions
	APU_DECLARE_NONSTD (void) apr_dynamic_fn_register(const char *szName
	APU_DECLARE (apr_opt_fn_t *) apr_dynamic_fn_retrieve(const char *szName)

Variables
apr_opt_fn_t *	pfn

Detailed Description

Typesafe registration and retrieval of functions that may not be present (i.e. functions exported by optional modules)

Macro Definition Documentation

APR_DECLARE_OPTIONAL_FN

#define APR_DECLARE_OPTIONAL_FN	(		ret,
			name,
			args
	)		typedef ret (APR_OPTIONAL_FN_TYPE(name)) args

Declare an optional function.

Parameters

ret	The return type of the function
name	The name of the function
args	The function arguments (including brackets)

Definition at line 50 of file apr_optional.h.

APR_OPTIONAL_FN_TYPE

#define APR_OPTIONAL_FN_TYPE

(

name

)

apr_OFN_##name##_t

The type of an optional function.

Parameters

name	The name of the function

Definition at line 42 of file apr_optional.h.

APR_REGISTER_OPTIONAL_FN

#define APR_REGISTER_OPTIONAL_FN

(

name

)

Value:

  do { \
  APR_OPTIONAL_FN_TYPE(name) *apu__opt = name; \
  apr_dynamic_fn_register(#name,(apr_opt_fn_t *)apu__opt); \
} while (0)

Register an optional function. This can be later retrieved, type-safely, by name. Like all global functions, the name must be unique. Note that, confusingly but correctly, the function itself can be static!

Parameters

name	The name of the function

Definition at line 70 of file apr_optional.h.

APR_RETRIEVE_OPTIONAL_FN

#define APR_RETRIEVE_OPTIONAL_FN

(

name

)

(APR_OPTIONAL_FN_TYPE(name) *)apr_dynamic_fn_retrieve(#name)

Retrieve an optional function. Returns NULL if the function is not present.

Parameters

name	The name of the function

Definition at line 84 of file apr_optional.h.

Typedef Documentation

apr_opt_fn_t

typedef void() apr_opt_fn_t(void)

XXX: This doesn't belong here, then! Private function! DO NOT USE!

Definition at line 59 of file apr_optional.h.

Function Documentation

APU_DECLARE()

APU_DECLARE

(

apr_opt_fn_t *

)

const

APU_DECLARE_NONSTD()

APU_DECLARE_NONSTD

(

void

)

const

Variable Documentation

pfn

apr_opt_fn_t* pfn

Definition at line 62 of file apr_optional.h.