(guile.info.gz) Immediate objects

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(guile.info.gz) Relationship between SCM and scm_t_bits

(guile.info.gz) Unpacking the SCM type

(guile.info.gz) Non-immediate objects

 
 18.2.7.2 Immediate objects
 ..........................
 
 A Scheme object may either be an immediate, i.e. carrying all necessary
 information by itself, or it may contain a reference to a "cell" with
 additional information on the heap.  Although in general it should be
 irrelevant for user code whether an object is an immediate or not,
 within Guile's own code the distinction is sometimes of importance.
 Thus, the following low level macro is provided:
 
  -- Macro: int SCM_IMP (SCM X)
      A Scheme object is an immediate if it fulfills the `SCM_IMP'
      predicate, otherwise it holds an encoded reference to a heap cell.
      The result of the predicate is delivered as a C style boolean
      value.  User code and code that extends Guile should normally not
      be required to use this macro.
 
 Summary:
    * Given a Scheme object X of unknown type, check first with `SCM_IMP
      (X)' if it is an immediate object.
 
    * If so, all of the type and value information can be determined
      from the `scm_t_bits' value that is delivered by `SCM_UNPACK (X)'.
 

Info Catalog

(guile.info.gz) Relationship between SCM and scm_t_bits

(guile.info.gz) Unpacking the SCM type

(guile.info.gz) Non-immediate objects