![visual basic strings visual basic strings](https://i.ytimg.com/vi/o7hLwfTq5DY/maxresdefault.jpg)
- #Visual basic strings how to#
- #Visual basic strings full#
- #Visual basic strings code#
- #Visual basic strings series#
TestStr = Format(testDateTime, "hh:mm:ss tt") ' Returns the value of testDateTime in user-defined date/time formats.
#Visual basic strings code#
' format, using the single letter code for the format. ' Also returns current system date in the system-defined long date ' Returns current system date in the system-defined long date format. ' Returns current system time in the system-defined long time format. Finally, there is a two-byte null character at the end.For locales that use a 24-hour clock, the AM/PM indicators ( t and tt) display nothing. The characters are in the order expected, but the two bytes within each 16-bit code point are once again little-endian. When we do we indeed see a value of 10, for the 10 bytes of the 5-character Unicode string “Hello”. Again, this is little-endian so we have to reverse the bytes to correctly interpret it. The printout shows that calling StrPtr returns the exact same pointer value as in ptrBSTR.įinally, we actually display the bytes of the BSTR. Since my machine is little-endian the raw bytes appear backwards. First, when we directly read the memory at the address returned by VarPtr, we get the bytes of the pointer to the character buffer. The functions used and memory layout revealed take a little more explaining. The variable table in this case is pretty simple: Variables
#Visual basic strings full#
In the example below, I show the full BSTR structure by getting the length in bytes of the string buffer itself using LenB, back up 4 bytes to include the length field, and read a total of 6 extra bytes to include both the length field at the start and the null character at the end. In order to directly read this length field, then, we need to take the pointer returned by StrPtr and back up 4 bytes. However, the BSTR specification requires that implementers pass around the pointer to the start of the character buffer itself (rather than the preceding length field), so that a BSTR* can be passed directly to functions expecting pointers to C-style null-terminated strings. Note this length is in bytes, not characters, and it does not include the two bytes of the terminating null character. The BSTR structure actually starts with an unsigned 32-bit integer which indicates the length of the character buffer.
![visual basic strings visual basic strings](https://i.ytimg.com/vi/RZpi-v8_JQs/maxresdefault.jpg)
For a variable declared as a String, then, directly reading the memory at the address returned by VarPtr should give you the same pointer value as calling StrPtr.Īs noted in VBA Internals: What’s in a variable, strings in VBA are implemented using the COM BSTR structure. With VBA we can either get the address to the variable itself using VarPtr, or we can go straight to the start of the character buffer by using StrPtr.
![visual basic strings visual basic strings](http://vb.net-informations.com/string/img/split-string-vb.png)
The contents of a string variable is actually a pointer to another memory location where the actual string characters are stored. Pointers and memory for string variablesĮven though string variables are treated semantically as value types, they are reference types by implementation. See Scalar Variables and Pointers in Depth for additional background and for the code for the utility functions HexPtr and Mem_ReadHex. In this post, I will cover the details of string variables and pointers. Scalar Variables and Pointers in Depth – Details of numeric scalar variables and pointers.
#Visual basic strings how to#
#Visual basic strings series#
This is the next installment of a series of deep-dives into the structure and implementation of variables in Visual Basic for Applications.