Tcl_NewStringObj(), Tcl_NewUnicodeObj(), Tcl_SetStringObj(), Tcl_SetUnicodeObj(), Tcl_GetStringFromObj(), Tcl_GetString(), Tcl_GetUnicode(), Tcl_GetUniChar(), Tcl_GetCharLength(), Tcl_GetRange(), Tcl_AppendToObj(), Tcl_AppendUnicodeToObj(), Tcl_AppendStringsToObj(), Tcl_AppendStringsToObjVA(), Tcl_AppendObjToObj(), Tcl_SetObjLength(), Tcl_ConcatObj()

manipulate Tcl objects as strings 

Tcl Library Procedures


SYNOPSIS

#include <tcl.h>

Tcl_Obj * Tcl_NewStringObj(bytes, length)

Tcl_Obj * Tcl_NewUnicodeObj(unicode, numChars)

void Tcl_SetStringObj(objPtr, bytes, length)

void Tcl_SetUnicodeObj(objPtr, unicode, numChars)

char * Tcl_GetStringFromObj(objPtr, lengthPtr)

char * Tcl_GetString(objPtr)

Tcl_UniChar * Tcl_GetUnicode(objPtr)

Tcl_UniChar Tcl_GetUniChar(objPtr, index)

int Tcl_GetCharLength(objPtr)

Tcl_Obj * Tcl_GetRange(objPtr, first, last)

void Tcl_AppendToObj(objPtr, bytes, length)

void Tcl_AppendUnicodeToObj(objPtr, unicode, numChars)

void Tcl_AppendObjToObj(objPtr, appendObjPtr)

void Tcl_AppendStringsToObj(objPtr, string, string, ... (char *) NULL)

void Tcl_AppendStringsToObjVA(objPtr, argList)

void Tcl_SetObjLength(objPtr, newLength)

Tcl_Obj * Tcl_ConcatObj(objc, objv)


ARGUMENTS

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 length is negative.

int length (in) 

The number of bytes to copy from bytes when initializing, setting, or appending to a string object. If negative, all bytes up to the first null are used.

Tcl_UniChar *unicode (in) 

Points to the first byte of an array of Unicode characters used to set or append to a string object. This byte array may contain embedded null characters unless numChars is negative.

int numChars (in) 

The number of Unicode characters to copy from unicode when initializing, setting, or appending to a string object. If negative, all characters up to the first null character are used.

int index (in) 

The index of the Unicode character to return.

int first (in) 

The index of the first Unicode character in the Unicode range to be returned as a new object.

int last (in) 

The index of the last Unicode character in the Unicode range to be returned as a new object.

Tcl_Obj *objPtr (in/out) 

Points to an object to manipulate.

Tcl_Obj *appendObjPtr (in) 

The object to append to objPtr in Tcl_AppendObjToObj().

int *lengthPtr (out) 

If non-NULL, the location where Tcl_GetStringFromObj() will store the the length of an object's string representation.

char *string (in) 

Null-terminated string value to append to objPtr.

va_list argList (in) 

An argument list which must have been initialized using TCL_VARARGS_START, and cleared using va_end.

int newLength (in) 

New length for the string value of objPtr, not including the final NULL character.

int objc (in) 

The number of elements to concatenate.

Tcl_Obj *objv[] (in) 

The array of objects to concatenate.


DESCRIPTION

The procedures described in this reference page 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. Also, indexing and length computations are optimized because the Unicode string representation is calculated and cached as needed.

Tcl_NewStringObj() and Tcl_SetStringObj() create a new object or modify an existing object to hold a copy of the string given by bytes and length. Tcl_NewUnicodeObj() and Tcl_SetUnicodeObj() create a new object or modify an existing object to hold a copy of the Unicode string given by unicode and numChars. Tcl_NewStringObj() and Tcl_NewUnicodeObj() return a pointer to a newly created object with reference count zero. All four procedures set the object to hold a copy of the specified string. Tcl_SetStringObj() and Tcl_SetUnicodeObj() free any old string representation as well as any old internal representation of the object.

Tcl_GetStringFromObj() and Tcl_GetString() return an object's string representation. This is given by the returned byte pointer and (for Tcl_GetStringFromObj()) length, which is stored in lengthPtr if it is non-NULL. If the object's UTF 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. The procedure Tcl_GetString() is used in the common case where the caller does not need the length of the string representation.

Tcl_GetUnicode() returns an object's value as a Unicode string. Tcl_GetUniChar() returns the index'th character in the object's Unicode representation.

Tcl_GetRange() returns a newly created object comprised of the characters between first and last (inclusive) in the object's Unicode representation. If the object's Unicode representation is invalid, the Unicode representation is regenerated from the object's string representation.

Tcl_GetCharLength() returns the number of characters (as opposed to bytes) in the string object.

Tcl_AppendToObj() appends the data given by bytes and length to the string representation of the object specified by objPtr. If the object has an invalid string representation, then an attempt is made to convert bytes is to the Unicode format. If the conversion is successful, then the converted form of bytes is appended to the object's Unicode representation. Otherwise, the object's Unicode representation is invalidated and converted to the UTF format, and bytes is appended to the object's new string representation.

Tcl_AppendUnicodeToObj() appends the Unicode string given by unicode and numChars to the object specified by objPtr. If the object has an invalid Unicode representation, then unicode is converted to the UTF format and appended to the object's string representation. Appends are optimized to handle repeated appends relatively efficiently (it overallocates the string or Unicode space to avoid repeated reallocations and copies of object's string value).

Tcl_AppendObjToObj() is similar to Tcl_AppendToObj(), but it appends the string or Unicode value (whichever exists and is best suited to be appended to objPtr) of appendObjPtr to objPtr.

Tcl_AppendStringsToObj() is similar to Tcl_AppendToObj() except that it can be passed more than one value to append and each value must be a null-terminated string (that is, none of the values may contain internal null characters). Any number of string arguments may be provided, but the last argument must be a NULL pointer to indicate the end of the list.

Tcl_AppendStringsToObjVA() is the same as Tcl_AppendStringsToObj() except that instead of taking a variable number of arguments it takes an argument list.

The Tcl_SetObjLength() procedure changes the length of the string value of its objPtr argument. If the newLength 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 newLength argument is less than the current length of the object's string, with objPtr->length 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 Tcl_SetObjLength() without reallocating storage. In all cases Tcl_SetObjLength() leaves a null character at objPtr->bytes[newLength].

The Tcl_ConcatObj() function returns a new string object whose value is the space-separated concatenation of the string representations of all of the objects in the objv array. Tcl_ConcatObj() eliminates leading and trailing white space as it copies the string representations of the objv array to the result. If an element of the objv 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 concat command cleaner-looking. Tcl_ConcatObj() returns a pointer to a newly-created object whose ref count is zero.


PORTABILITY

Windows Server 2012. Windows 8.1. Windows Server 2012 R2. Windows 10. Windows Server 2016. Windows Server 2019.


AVAILABILITY

PTC MKS Toolkit for Professional Developers
PTC MKS Toolkit for Enterprise Developers
PTC MKS Toolkit for Enterprise Developers 64-Bit Edition


SEE ALSO

Functions:
Tcl_DecrRefCount(), Tcl_IncrRefCount(), Tcl_NewObj()


PTC MKS Toolkit 10.3 Documentation Build 39.