> ## Documentation Index
> Fetch the complete documentation index at: https://docs.syntblaze.com/llms.txt
> Use this file to discover all available pages before exploring further.
# PHP Bitwise OR
The `|` operator in PHP is the bitwise inclusive OR operator. It evaluates the binary representations of two operands and performs a logical OR operation on each corresponding pair of bits. If a bit is `1` in the left operand, the right operand, or both, the corresponding bit in the result is set to `1`. The result bit is `0` only if both corresponding operand bits are `0`.
```php theme={"dark"}
$result = $operand1 | $operand2;
```
## Truth Table
\| Bit A | Bit B | Result (`A | B`) |
\| :---: | :---: | :---: |
\| 0 | 0 | 0 |
\| 0 | 1 | 1 |
\| 1 | 0 | 1 |
\| 1 | 1 | 1 |
## Integer Evaluation
When operating on integers, the engine aligns the binary sequences of both numbers and evaluates them bit-by-bit.
```php theme={"dark"}
$a = 5; // Binary representation: 0000 0101
$b = 3; // Binary representation: 0000 0011
$result = $a | $b;
// Evaluation: 0000 0111
// Decimal output: 7
```
## String Evaluation
If *both* operands are strings, PHP performs the bitwise OR operation byte-by-byte, evaluating the underlying ASCII/byte values of the characters.
```php theme={"dark"}
$str1 = "A"; // ASCII 65, Binary: 0100 0001
$str2 = " "; // ASCII 32, Binary: 0010 0000
$result = $str1 | $str2;
// Evaluation: 0110 0001
// ASCII output: 97 (String: "a")
```
**String Length Discrepancies:** If the two string operands are of unequal length, the bitwise operation is performed up to the length of the *longer* string. The shorter string is treated as if it were padded with null bytes (`\x00`) to match the length of the longer string. Because a bitwise OR operation between any byte and a null byte (`0000 0000`) results in the original byte, the remaining trailing bytes of the longer string are appended to the result unmodified.
## Type Coercion Rules
The `|` operator enforces specific type juggling behaviors depending on the operands provided:
* **Float to Integer:** If an operand is a floating-point number, PHP truncates the fractional part and casts it to an integer before performing the bitwise operation.
* **Mixed Types (String and Int):** The byte-by-byte string evaluation is strictly reserved for when *both* operands are strings. If one operand is a string and the other is an integer (or float), the string must be a well-formed numeric string, which PHP will cast to an integer prior to evaluation. As of PHP 8.0, if the string is non-numeric, applying the `|` operator throws a `TypeError` rather than silently casting the string to `0`.
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