_READBIT - QB64Official/qb64 GitHub Wiki

The _READBIT function is used to check the state of a specified bit of a integer value.

Syntax

result = _READBIT(numericalVariable, numericalValue)

Parameter(s)

  • numericalVariable is the variable to read the state of a bit of and can be of the following types: _BYTE, INTEGER, LONG, or _INTEGER64.
  • Integer values can be signed or _UNSIGNED.
  • numericalValue the number of the bit to be read.

Description

  • Used to check the current state of a bit in an integer value.
  • Returns -1 if the bit is set(1), otherwise returns 0 if the bit is not set(0)
  • Bits start at 0 (so a _BYTE has bits 0 to 7, INTEGER 0 to 15, and so on)

Availability

  • Version 1.4 and up.

Example(s)


A~%% = _SETBIT(A~%%,4)
PRINT "Bit 4 is currently ";
IF _READBIT(A~%%,4) = -1 THEN PRINT "ON" ELSE PRINT "OFF"
PRINT "And bit 2 is currently ";
IF _READBIT(A~%%,2) = -1 THEN PRINT "ON" ELSE PRINT "OFF"


Bit 4 is currently ON
And bit 2 is currently OFF


B& = 12589575
PRINT "B& ="; B&
FOR I%% = 31 TO 0 STEP -1 '32 bits for a LONG value
 Binary$ = Binary$ + LTRIM$(STR$(ABS(_READBIT(B&, I%%))))
NEXT I%%
PRINT "B& in binary is: "; Binary$


B& = 12589575
B& in binary is: 00000000110000000001101000000111

See Also