From QB64.org wiki
An underscore can be used at the end of a line of code to continue a code line to the next line.
Usage: IF x + y > 500 AND x + y < 600 THEN_
- PRINT x + y
- Only QB64 keywords can use a leading underscore! Leading underscores are reserved for QB64 procedure names only!
- The underscore can be anywhere after the code on that line to continue the code to the next line in QB64.
- Multiple underscores can be used for the same line of code in QB64 only.
- Underscores can be used in the middle of variable, sub procedure or constant names.
- The underscore is NOT compatible with Qbasic! The Qbasic IDE will remove or move code with leading underscores!
- In PRINT USING an underscore can precede a formatting character to display that character as text in a template STRING.