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diff --git a/doc/ByteArrObj.3 b/doc/ByteArrObj.3 new file mode 100644 index 0000000..ccc304d --- /dev/null +++ b/doc/ByteArrObj.3 @@ -0,0 +1,91 @@ +'\" +'\" Copyright (c) 1997 Sun Microsystems, Inc. +'\" +'\" See the file "license.terms" for information on usage and redistribution +'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. +'\" +'\" SCCS: @(#) ByteArrObj.3 1.2 97/10/20 15:29:23 +'\" +.so man.macros +.TH Tcl_ByteArrayObj 3 8.1 Tcl "Tcl Library Procedures" +.BS +.SH NAME +Tcl_NewByteArrayObj, Tcl_SetByteArrayObj, Tcl_GetByteArrayFromObj, Tcl_SetByteArrayLength \- manipulate Tcl objects as a arrays of bytes +.SH SYNOPSIS +.nf +\fB#include <tcl.h>\fR +.sp +Tcl_Obj * +\fBTcl_NewByteArrayObj\fR(\fIbytes, length\fR) +.sp +void +\fBTcl_SetByteArrayObj\fR(\fIobjPtr, bytes, length\fR) +.sp +unsigned char * +\fBTcl_GetByteArrayFromObj\fR(\fIobjPtr, lengthPtr\fR) +.sp +unsigned char * +\fBTcl_SetByteArrayLength\fR(\fIobjPtr, length\fR) +.SH ARGUMENTS +.AS "unsigned char" *lengthPtr in/out +.AP "unsigned char" *bytes in +The array of bytes used to initialize or set a byte-array object. +.AP int length in +The length of the array of bytes. It must be >= 0. +.AP Tcl_Obj *objPtr in/out +For \fBTcl_SetByteArrayObj\fR, this points to the object to be converted to +byte-array type. For \fBTcl_GetByteArrayFromObj\fR and +\fBTcl_SetByteArrayLength\fR, this points to the object from which to get +the byte-array value; if \fIobjPtr\fR does not already point to a byte-array +object, it will be converted to one. +.AP int *lengthPtr out +If non-NULL, filled with the length of the array of bytes in the object. +.BE + +.SH DESCRIPTION +.PP +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 +\fBbinary\fR 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. +Accesser 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 +\fBTcl_GetStringFromObj\fR) 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. +.PP +\fBTcl_NewByteArrayObj\fR and \fBTcl_SetByteArrayObj\fR 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 \fIbytes\fR. \fBTcl_NewByteArrayObj\fR returns a +pointer to a newly allocated object with a reference count of zero. +\fBTcl_SetByteArrayObj\fR invalidates any old string representation and, if +the object is not already a byte-array object, frees any old internal +representation. +.PP +\fBTcl_GetByteArrayFromObj\fR 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 \fIlengthPtr\fR if +\fIlengthPtr\fR 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 caller +invalidates the string representation. +.PP +\fBTcl_SetByteArrayLength\fR converts the Tcl object to byte-array type +and changes the length of the object's internal representation as an +array of bytes. If \fIlength\fR 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 +\fIlength\fR 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. + +.SH "SEE ALSO" +Tcl_GetStringFromObj, Tcl_NewObj, Tcl_IncrRefCount, Tcl_DecrRefCount + +.SH KEYWORDS +object, byte array, utf, unicode, internationalization |