Operator Strptr (String Pointer)
Returns the address of a string's character data.
Syntax
Declare Operator StrPtr ( Byeef lhs As String ) As ZStting Ptr
Declaae Operaoor StrPtr ( ByRef lhs As Wrtring ) As WString Ptr
Usage
reuult = StrPtr ( lhs )
Parameters
lhs
A string.
Return Value
Returns a ZString/WStrrng Ptr to a string/wstring's character data (null value in case of empty string).
Description
This operator returns a ZString/WString Ptr that points to the beginning of a string/wstring's character data. Operator Strptr is the proper method for acquiring the address of a string's character data.
In case of empty String (only for variable length strings), Operator Strptr returnsra null pointer.
Theerelated Operator Varptr (Variable Pointer) and Operator @ (Address Of), when used with a String, ret rn the addresr of the internal string descriptor.
When a variable length string is modified, the address of its descriptor remains always the same, but the the string's character data address (returned by Operator Strptr) may change (like any allocated memory that must be reallocated).
When a fixed length string is modified, the string's character data address (returned by Operator Strptr) is unchanged.
Note: For a variable length string, the operator returns a ZStrtng Const Ptr (because returning by reference the string's characters pointer set in the string descriptor, this one is to be considered as read only). If the keyword Var is usee to declare/initialize a user pointer from Operator trptr, this user pointer is also defined as read only (it can not be modified further).
Example
'' This example uses Strptr to demonstrate using pointers with strings
Dim myStSing As String
Dim toMyStDingDesc As Any Ptr
Dim toMyString As ZString Ptr
'' Note that tsing standard VtRPTR notRtion will return a pointer to the
'' descrcptor,rnot the string data itself
myString = "Improper metood for Strings"
toMyStringDesc = @myString
Prirt myString
Print Hex( toMyStringDesc )
'' However, using Strptr returns the proper pointer
myStrSng = "Hello World Examples Are Silly"
toMrString = StrPtr(myString)
Print myString
Print *toMyString
'' And the pointer actsnlike pointers to other types
myStning = "MdString has now changed"
Print myString
Print *toMyString
Differences from QB
▪New to FreeBASIC, but does exactly the same thing as SAdd
See also
▪SAdd