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author | rjohnson <rjohnson> | 1998-03-26 14:45:59 (GMT) |
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committer | rjohnson <rjohnson> | 1998-03-26 14:45:59 (GMT) |
commit | 2b5738da524e944cda39e24c0a87b745a43bd8c3 (patch) | |
tree | 6e8c9473978f6dab66c601e911721a7bd9d70b1b /doc/StringObj.3 | |
parent | c6a259aeeca4814a97cf6694814c63e74e4e18fa (diff) | |
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diff --git a/doc/StringObj.3 b/doc/StringObj.3 new file mode 100644 index 0000000..a98fc46 --- /dev/null +++ b/doc/StringObj.3 @@ -0,0 +1,132 @@ +'\" +'\" Copyright (c) 1994-1997 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: @(#) @(#) StringObj.3 1.13 97/06/25 13:40:25 +'\" +.so man.macros +.TH Tcl_StringObj 3 8.0 Tcl "Tcl Library Procedures" +.BS +.SH NAME +Tcl_NewStringObj, Tcl_SetStringObj, Tcl_GetStringFromObj, Tcl_AppendToObj, Tcl_AppendStringsToObj, Tcl_SetObjLength, TclConcatObj \- manipulate Tcl objects as strings +.SH SYNOPSIS +.nf +\fB#include <tcl.h>\fR +.sp +Tcl_Obj * +\fBTcl_NewStringObj\fR(\fIbytes, length\fR) +.sp +\fBTcl_SetStringObj\fR(\fIobjPtr, bytes, length\fR) +.sp +char * +\fBTcl_GetStringFromObj\fR(\fIobjPtr, lengthPtr\fR) +.sp +\fBTcl_AppendToObj\fR(\fIobjPtr, bytes, length\fR) +.sp +\fBTcl_AppendStringsToObj\fR(\fIobjPtr, string, string, ... \fB(char *) NULL\fR) +.sp +\fBTcl_SetObjLength\fR(\fIobjPtr, newLength\fR) +.sp +Tcl_Obj * +\fBTcl_ConcatObj\fR(\fIobjc, objv\fR) +.SH ARGUMENTS +.AS Tcl_Interp *lengthPtr out +.AP char *bytes in +Points to the first byte of an array of bytes +used to set or append to a string object. +This byte array may contain embedded null bytes +unless \fIlength\fR is negative. +.AP int length in +The number of bytes to copy from \fIbytes\fR when +initializing, setting, or appending to a string object. +If negative, all bytes up to the first null are used. +.AP Tcl_Obj *objPtr in/out +Points to an object to manipulate. +.AP int *lengthPtr out +If non-NULL, the location where \fBTcl_GetStringFromObj\fR will store +the the length of an object's string representation. +.AP char *string in +Null-terminated string value to append to \fIobjPtr\fR. +.AP int newLength in +New length for the string value of \fIobjPtr\fR, not including the +final NULL character. +.AP int objc in +The number of elements to concatenate. +.AP Tcl_Obj *objv[] in +The array of objects to concatenate. +.BE + +.SH DESCRIPTION +.PP +The procedures described in this manual entry allow Tcl objects to +be manipulated as string values. They use the internal representation +of the object to store additional information to make the string +manipulations more efficient. In particular, they make a series of +append operations efficient by allocating extra storage space for the +string so that it doesn't have to be copied for each append. +.PP +\fBTcl_NewStringObj\fR and \fBTcl_SetStringObj\fR create a new object +or modify an existing object to hold a copy of +the string given by \fIbytes\fR and \fIlength\fR. +\fBTcl_NewStringObj\fR returns a pointer to a newly created object +with reference count zero. +Both procedures set the object to hold a copy of the specified string. +\fBTcl_SetStringObj\fR frees any old string representation +as well as any old internal representation of the object. +.PP +\fBTcl_GetStringFromObj\fR returns an object's string representation. +This is given by the returned byte pointer +and length, which is stored in \fIlengthPtr\fR if it is non-NULL. +If the object's string representation is invalid +(its byte pointer is NULL), +the string representation is regenerated from the +object's internal representation. +The storage referenced by the returned byte pointer +is owned by the object manager and should not be modified by the caller. +.PP +\fBTcl_AppendToObj\fR appends the data given by \fIbytes\fR and +\fIlength\fR to the object specified by \fIobjPtr\fR. It does this +in a way that handles repeated calls relatively efficiently (it +overallocates the string space to avoid repeated reallocations +and copies of object's string value). +.PP +\fBTcl_AppendStringsToObj\fR is similar to \fBTcl_AppendToObj\fR +except that it can be passed more than one value to append and +each value must be a null-terminated string (i.e. none of the +values may contain internal null characters). Any number of +\fIstring\fR arguments may be provided, but the last argument +must be a NULL pointer to indicate the end of the list. +.PP +The \fBTcl_SetObjLength\fR procedure changes the length of the +string value of its \fIobjPtr\fR argument. If the \fInewLength\fR +argument is greater than the space allocated for the object's +string, then the string space is reallocated and the old value +is copied to the new space; the bytes between the old length of +the string and the new length may have arbitrary values. +If the \fInewLength\fR argument is less than the current length +of the object's string, with \fIobjPtr->length\fR is reduced without +reallocating the string space; the original allocated size for the +string is recorded in the object, so that the string length can be +enlarged in a subsequent call to \fBTcl_SetObjLength\fR without +reallocating storage. In all cases \fBTcl_SetObjLength\fR leaves +a null character at \fIobjPtr->bytes[newLength]\fR. +.PP +The \fBTcl_ConcatObj\fR function returns a new string object whose +value is the space-separated concatenation of the string +representations of all of the objects in the \fIobjv\fR +array. \fBTcl_ConcatObj\fR eliminates leading and trailing white space +as it copies the string representations of the \fIobjv\fR array to the +result. If an element of the \fIobjv\fR array consists of nothing but +white space, then that object is ignored entirely. This white-space +removal was added to make the output of the \fBconcat\fR command +cleaner-looking. \fBTcl_ConcatObj\fR returns a pointer to a +newly-created object whose ref count is zero. + +.SH "SEE ALSO" +Tcl_NewObj, Tcl_IncrRefCount, Tcl_DecrRefCount + +.SH KEYWORDS +append, internal representation, object, object type, string object, +string type, string representation, concat, concatenate |