Caché MultiValue Basic Reference
BITSET


Sets the specified bit in a bitstring to 1.
Synopsis
Arguments
Description
The
BITSET function sets a single bit of
bitstring to 1 at the bit location specified by
bitno. Both values are specified as positive integers.
bitno always sets the specified bit to 1. If the bit specified by
bitno has a value of 0,
BITSET sets it to 1. If the bit specified by
bitno already has a value of 1,
BITSET sets it to 1 (leaves it unchanged).
Both
bitstring and
bitno can be expressed as either numbers or as strings. These numbers are converted to canonical form, with leading plus signs and leading and trailing zeros omitted. If either argument evaluates to the null string or a nonnumeric string it is assumed to have a value of 0. A string is parsed as a number until a nonnumeric character is encountered. Thus “7dwarves” is parsed as 7.
If
bitno is specified as a decimal fraction it is truncated to its integer component.
The
BITSET function sets a specified bit to 1. The
BITRESET function sets a specified bit to 0. The
BITNOT function sets a specified bit to its opposite value.
Examples
The following example specifies a
bitstring of either 0 or 1. It then sets the bit position specified in
bitno to bit value 1:
PRINT BITSET(0,0); ! Sets bit position 0 to 1; returns integer 1
PRINT BITSET(0,1); ! Sets bit position 1 to 1; returns integer 2
PRINT BITSET(1,0); ! Sets bit position 0 to 1; returns integer 1
PRINT BITSET(1,1); ! Sets bit position 1 to 1; returns integer 3
The following example specifies a
bitstring of 64 (binary 1000000), and
bitno sets bit position 0 to the bit value 1. This results in the binary string 1000001, the integer value of which is 65:
PRINT BITSET(64,0); ! Returns 65
The following example specifies a
bitstring of 64 (binary 1000000), and
bitno sets bit position 4 to the bit value 1. This results in the binary string 1010000, the integer value of which is 80:
PRINT BITSET(64,4); ! Returns 80
The following example specifies a
bitstring of 65 (binary 1000001), and
bitno specifies setting bit position 0 to the bit value 1. But because bit position 0 already has a bit value of 1, the binary string 1000001 (integer value 65) is returned unchanged:
PRINT BITSET(65,0); ! Returns 65
The following example specifies a
bitstring of 8 (binary 1000), and
bitno specifies setting bit position 4 to the bit value 1. The
bitstring has an implicit bit position of 4 with a value of 0. Setting this bit to 1 returns the binary string 11000, the integer value of which is 24:
PRINT BITSET(8,4); ! Returns 24
The following example specifies
bitstring and
bitno with null string values. The null string is parsed as 0:
PRINT BITSET("",1); ! Returns 2; same as BITSET(0,1)
PRINT BITSET(1,""); ! Returns 1; same as BITSET(1,0)
PRINT BITSET("",""); ! Returns 1; same as BITSET(0,0)
See Also