1Tcl_BooleanObj(3) Tcl Library Procedures Tcl_BooleanObj(3)
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6
8 Tcl_NewBooleanObj, Tcl_SetBooleanObj, Tcl_GetBooleanFromObj - manipu‐
9 late Tcl objects as boolean values
10
12 #include <tcl.h>
13 Tcl_Obj *
15 Tcl_NewBooleanObj(boolValue)
16 Tcl_SetBooleanObj(objPtr, boolValue)
18 int
20 Tcl_GetBooleanFromObj(interp, objPtr, boolPtr)
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23 int boolValue (in) Integer value used to initialize or
24 set a boolean object. If the integer
25 is nonzero, the boolean object is set
26 to 1; otherwise the boolean object is
27 set to 0.
28 Tcl_Obj *objPtr (in/out) For Tcl_SetBooleanObj, this points to
30 the object to be converted to boolean
31 type. For Tcl_GetBooleanFromObj, this
32 refers to the object from which to get
33 a boolean value; if objPtr does not
34 already point to a boolean object, an
35 attempt will be made to convert it to
36 one.
37 Tcl_Interp *interp (in/out) If an error occurs during conversion,
39 an error message is left in the inter‐
40 preter's result object unless interp
41 is NULL.
42 int *boolPtr (out) Points to place where Tcl_GetBoolean‐
44 FromObj stores the boolean value (0 or
45 1) obtained from objPtr.
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50 These procedures are used to create, modify, and read boolean Tcl
51 objects from C code. Tcl_NewBooleanObj and Tcl_SetBooleanObj will cre‐
52 ate a new object of boolean type or modify an existing object to have
53 boolean type. Both of these procedures set the object to have the
54 boolean value (0 or 1) specified by boolValue; if boolValue is nonzero,
55 the object is set to 1, otherwise to 0. Tcl_NewBooleanObj returns a
56 pointer to a newly created object with reference count zero. Both pro‐
57 cedures set the object's type to be boolean and assign the boolean
58 value to the object's internal representation longValue member.
59 Tcl_SetBooleanObj invalidates any old string representation and, if the
60 object is not already a boolean object, frees any old internal repre‐
61 sentation.
62 Tcl_GetBooleanFromObj attempts to return a boolean value from the Tcl
64 object objPtr. If the object is not already a boolean object, it will
65 attempt to convert it to one. If an error occurs during conversion, it
66 returns TCL_ERROR and leaves an error message in the interpreter's
67 result object unless interp is NULL. Otherwise, Tcl_GetBooleanFromObj
68 returns TCL_OK and stores the boolean value in the address given by
69 boolPtr. If the object is not already a boolean object, the conversion
70 will free any old internal representation. Objects having a string
71 representation equal to any of 0, false, no, or off have a boolean
72 value 0; if the string representation is any of 1, true, yes, or on the
73 boolean value is 1. Any of these string values may be abbreviated, and
74 upper-case spellings are also acceptable.
75
78 Tcl_NewObj, Tcl_DecrRefCount, Tcl_IncrRefCount, Tcl_GetObjResult
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82 boolean, boolean object, boolean type, internal representation, object,
83 object type, string representation
84Tcl 8.0 Tcl_BooleanObj(3)