c_alloc/[2,3]

Module: builtins

c_const/2 — get the value of a C defined constant
c_rconst/2 — get the value of a C defined runtime constant
c_alloc/2 — allocate a UIA that can hold C data
c_alloc_abs/2 — allocate a C-malloced data area
c_allocn/3 — allocate a UIA to hold Num items
c_allocn_abs/3 — allocated a C-malloced area to hold Num items
c_free/1 — applied to UIA does nothing (freeing handled by gc)
c_free_abs/1 — mfree the C area pointed by Ptr.
c_set/3 — modify a UIA or C data area
c_set/3 — multiply modify a UIA or C data area
c_set_str/4 — insert C string in a UIA or C data area
c_set_raw/4 — writes chars from a UIA into a UIA or C data area
c_setn/4 — perform c_set/3 on a component of an array
c_setn/4 — multiply perform c_set/3 on a component of an array
c_examine/3 — examine a UIA or C data area
c_examine/3 — multiply examine a UIA or C data area
c_examine_str/4 — extract chars from a UIA or C data area
c_examine_raw/4 — extract raw chars from a UIA or C data area
c_examinen/4 — examine a component of an array
c_examinen/4 — multiply examine a component of an array

FORMS

c_const(Name,Val)

c_rconst(Name,Val)

c_alloc(Type,UIA)

c_alloc_abs(Type,Ptr)

c_allocn(Type,Num,UIA)

c_allocn_abs(Type,Num,Ptr)

c_free(UIA)

c_free_abs(Ptr)

c_set(Obj,Type1,Val)

c_set(Obj,Type2,[FieldName,Val,...])

c_set_str(Obj,Off,Len,SymOrUIA)

c_set_raw(Obj,Off,Len,UIA)

c_setn(Obj,Type,I,Val)

c_setn(Obj,SType,I,[FieldName,Val,...])

c_examine(Obj,Type,Val)

c_examine(Obj,SType,[FieldName,Val,...])

c_examine_str(Obj,Off,Len,Val)

c_examine_raw(Obj,Off,Len,Val)

c_examinen(Obj,Type,I,Val)

c_examinen(Obj,SType,I,[FieldName,Val,...])

DESCRIPTION

These predicates make use of the same C type encoding as used on ‘$c_malloc’/2:

      1  -- int
      2  -- unsigned int
      3  -- long
      4  -- unsigned long
      5  -- pointer
      6  -- char
      7  -- unsigned char
      8  -- short
      9  -- unsigned short
      10 -- string
      11 -- string of given length (length is 4th arg)
      12 -- float
      13 -- double
      14 -- far pointer  (DOS only)
      15 -- raw data of given length

c_const(Name,Val) unifies Val with the value of the C defined constant Name.

c_rconst(Name,Val) unifies Val with the value of a C defined runtime constant Name. This should not be used to access C globals.

c_alloc(Type,UIA) allocates a UIA that can hold data of type Type.

c_alloc_abs(Type,Ptr) mallocs a C data area that can hold data of type Type and unifies Ptr with the address of the first byte of that area.

c_allocn(Type,Num,UIA) allocates a UIA that can hold Num items of type Type.

c_allocn_abs(Type,Num,Ptr) mallocs a C data area that can hold data of type Type and unifies Ptr with the address of the first byte of that area.

c_free(UIA) is a no-op, doing nothing (allowing freeing taken care of by gc).

c_free_abs(Ptr) C mfrees the C data area pointed to by Ptr.

c_set(Entity,Type,Val) destructively modifies an Entity (a UIA or C data area), where Val is of type Type, by using Val to replace a segment of Entity starting at the beginning of Entity.

c_set(Obj,Type2,[FieldName,Val,...]) destructively modify a UIA or C data area Obj with Val of type Type2. Type2 must be a structure type, and FieldName is the name of a field to be modified with value Val. Subfields are identified by their (C-style) dot-separated pathname, except when the sub-structure is a type-reference, in which case FieldName is the name of the field, and Val is (recursively) a list of FieldName - Value pairs.

c_set_str(Obj,Off,Len,SymOrUIA) destructively modify a segment of data in the UIA or C data Obj at an offset Off by no more than Len bytes taken from SymOrUIA.

c_set_raw(Obj,Off,Len,UIA) writes Len characters from UIA into Obj starting at offset Off.

c_setn(Obj,Type,I,Val)
c_setn(Obj,SType,I,[FieldName,Val,...]) perform c_set/3 on the I-th component of an array, where I=0 refers to the first element and so on. In the first form, Type must be a base type. In the second form SType must be a structure type (substructures are handled in the same manner as in c_set/3).

c_examine(Obj,Type,Val)
c_examine(Obj,SType,[FieldName,Val,...]) examine a UIA or C ptr Obj, assuming its type to be Type. In the first form, Type is either an intergral type or 'str'. In the second form, SType must be a structure type.

c_examine_str(Obj,Off,Len,Val) examine a segment of Obj starting at offset Off until first null character or Len characters have been read, whichever comes first and return the value as as a UIA in Val.

c_examine_raw(Obj,Off,Len,Val) reads Len characters starting at offset Off into Obj and returns the result as a UIA in Val. Note that the resulting UIA can have null and other funny characters.

c_examinen(Obj,Type,I,Val)
c_examinen(Obj,SType,I,[FieldName,Val,...]) examine the I-th the component of an array of type Type/SType.

NOTES

Implemented in ~builtins/cutils.pro over the predicates in ‘$c_malloc’/2.

SEE ALSO

• '$c_malloc'/2
• c_create/3