Topic       : C-Language Documentation
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View Ref-File[ Function Pointers ]

... are variables which store the starting address of a function.
De-referencing a function pointer means executing that function.
Otherwise they are like any other pointer variable.

The most common application for function pointers is as a function
parameter so that one can execute a function (or several different
functions) inside another (older) function (as is done by signal
and Supexec).

Definition Syntax:

 [<class>] [<type>] [<parm>] (* <name>) (<type> <arg name> [, ...] );

where <class> is the storage class of the pointer,
<type> is a data type of the function,
<parm> is either 'cdecl' or 'pascal',
<name> is the pointer name, and
<arg name> is a dummy argument name.

Calling Syntax:

   (* <name>) ( <arg> [, ...] )

where the value of <arg> is passed to the corresponding <arg name>.

Example:

  int (* write_string) (const char *s);

  write_string = puts;
  (* write_string) ("Hello world! \n");