Apache Portable Runtime
Defines | Typedefs | Functions
Optional Functions
Apache Portability Runtime library

Defines

#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

void apr_dynamic_fn_register (const char *szName, apr_opt_fn_t *pfn)
apr_opt_fn_tapr_dynamic_fn_retrieve (const char *szName)

Detailed Description

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


Define Documentation

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

Declare an optional function.

Parameters:
retThe return type of the function
nameThe name of the function
argsThe function arguments (including brackets)
#define APR_OPTIONAL_FN_TYPE (   name)    apr_OFN_##name##_t

The type of an optional function.

Parameters:
nameThe name of the function
#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:
nameThe name of the function
#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:
nameThe name of the function

Typedef Documentation

typedef void( apr_opt_fn_t)(void)

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

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