Tcl_ByteArrayObj(3)					      Tcl Library Procedures					       Tcl_ByteArrayObj(3)

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NAME

       Tcl_NewByteArrayObj, Tcl_SetByteArrayObj, Tcl_GetByteArrayFromObj, Tcl_SetByteArrayLength - manipulate Tcl objects as a arrays of bytes

SYNOPSIS

       #include <tcl.h>

       Tcl_Obj *
       Tcl_NewByteArrayObj(bytes, length)

       void
       Tcl_SetByteArrayObj(objPtr, bytes, length)

       unsigned char *
       Tcl_GetByteArrayFromObj(objPtr, lengthPtr)

       unsigned char *
       Tcl_SetByteArrayLength(objPtr, length)

ARGUMENTS

       const unsigned char *bytes (in)		    The array of bytes used to initialize or set a byte-array object.

       int length (in)				    The length of the array of bytes.  It must be >= 0.

       Tcl_Obj *objPtr (in/out) 		    For  Tcl_SetByteArrayObj,  this  points to the object to be converted to byte-array type.  For
						    Tcl_GetByteArrayFromObj and Tcl_SetByteArrayLength, this points to the object  from  which	to
						    get  the byte-array value; if objPtr does not already point to a byte-array object, it will be
						    converted to one.

       int *lengthPtr (out)			    If non-NULL, filled with the length of the array of bytes in the object.
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DESCRIPTION

       These procedures are used to create, modify, and read Tcl byte-array objects from C code.  Byte-array objects are typically  used  to  hold
       the  results  of binary IO operations or data structures created with the binary command.  In Tcl, an array of bytes is not equivalent to a
       string.	Conceptually, a string is an array of Unicode characters, while a byte-array is an array of  8-bit  quantities	with  no  implicit
       meaning.   Accessor  functions  are  provided to get the string representation of a byte-array or to convert an arbitrary object to a byte-
       array.  Obtaining the string representation of a byte-array object (by calling  Tcl_GetStringFromObj)  produces	a  properly  formed  UTF-8
       sequence with a one-to-one mapping between the bytes in the internal representation and the UTF-8 characters in the string representation.

       Tcl_NewByteArrayObj  and  Tcl_SetByteArrayObj will create a new object of byte-array type or modify an existing object to have a byte-array
       type.  Both of these procedures set the object's type to be byte-array and set the object's internal representation to a copy of the  array
       of  bytes given by bytes. Tcl_NewByteArrayObj returns a pointer to a newly allocated object with a reference count of zero.  Tcl_SetByteAr-
       rayObj invalidates any old string representation and, if the object is not already a byte-array object, frees any old internal  representa-
       tion.

       Tcl_GetByteArrayFromObj	converts  a  Tcl object to byte-array type and returns a pointer to the object's new internal representation as an
       array of bytes.	The length of this array is stored in lengthPtr if lengthPtr is non-NULL.  The storage for the array of bytes is owned	by
       the object and should not be freed.  The contents of the array may be modified by the caller only if the object is not shared and the call-
       er invalidates the string representation.

       Tcl_SetByteArrayLength converts the Tcl object to byte-array type and changes the length of the	object's  internal  representation  as	an
       array  of  bytes.   If  length is greater than the space currently allocated for the array, the array is reallocated to the new length; the
       newly allocated bytes at the end of the array have arbitrary values.  If length is less than the space currently allocated for  the  array,
       the length of array is reduced to the new length.  The return value is a pointer to the object's new array of bytes.

SEE ALSO

       Tcl_GetStringFromObj, Tcl_NewObj, Tcl_IncrRefCount, Tcl_DecrRefCount

KEYWORDS

       object, byte array, utf, unicode, internationalization

Tcl									8.1						       Tcl_ByteArrayObj(3)