Hook probe capability
[Hook Functions]

Defines
#define	APR_HOOK_INT_DCL_UD
#define	APR_HOOK_PROBE_ENTRY(ud, ns, name, args)
#define	APR_HOOK_PROBE_RETURN(ud, ns, name, rv, args)
#define	APR_HOOK_PROBE_INVOKE(ud, ns, name, src, args)
#define	APR_HOOK_PROBE_COMPLETE(ud, ns, name, src, rv, args)

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Detailed Description

APR hooks provide a trace probe capability for capturing the flow of control and return values with hooks.

In order to use this facility, the application must define the symbol APR_HOOK_PROBES_ENABLED and the four APR_HOOK_PROBE_ macros described below before including apr_hooks.h in files that use the APR_IMPLEMENT_EXTERNAL_HOOK_* macros.

This probe facility is not provided for APR optional hooks.

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Define Documentation

#define APR_HOOK_INT_DCL_UD

internal implementation detail to avoid the ud declaration when hook probes are not used

#define APR_HOOK_PROBE_COMPLETE	(	ud,
		ns,
		name,
		src,
		rv,
		args		)

User-defined hook probe macro that is invoked after calling a hook function.

Parameters:

ud

A void * user data field that was filled in by the user- provided APR_HOOK_PROBE_ENTRY(). Parameters: ns  The namespace prefix of the hook functions Parameters: name  The name of the hook Parameters: src  The value of apr_hook_debug_current at the time the function was hooked (usually the source file implementing the hook function). Parameters: rv  The return value of the hook function, or 0 if the hook is void. Parameters: args  The argument list to the hook functions, with enclosing parens.

#define APR_HOOK_PROBE_ENTRY	(	ud,
		ns,
		name,
		args		)

User-defined hook probe macro that is invoked when the hook is run, before calling any hook functions.

Parameters:

ud

A void * user data field that should be filled in by this macro, and will be provided to the other hook probe macros. Parameters: ns  The namespace prefix of the hook functions Parameters: name  The name of the hook Parameters: args  The argument list to the hook functions, with enclosing parens.

#define APR_HOOK_PROBE_INVOKE	(	ud,
		ns,
		name,
		src,
		args		)

User-defined hook probe macro that is invoked before calling a hook function.

Parameters:

ud

A void * user data field that was filled in by the user- provided APR_HOOK_PROBE_ENTRY(). Parameters: ns  The namespace prefix of the hook functions Parameters: name  The name of the hook Parameters: src  The value of apr_hook_debug_current at the time the function was hooked (usually the source file implementing the hook function). Parameters: args  The argument list to the hook functions, with enclosing parens.

#define APR_HOOK_PROBE_RETURN	(	ud,
		ns,
		name,
		rv,
		args		)

User-defined hook probe macro that is invoked after the hook has run.

Parameters:

ud

A void * user data field that was filled in by the user- provided APR_HOOK_PROBE_ENTRY(). Parameters: ns  The namespace prefix of the hook functions Parameters: name  The name of the hook Parameters: rv  The return value of the hook, or 0 if the hook is void. Parameters: args  The argument list to the hook functions, with enclosing parens.