Retrieving 64-bit Integer Values

The ValueInt64() method provides a direct, type-safe way to retrieve the value of a uCalc variable defined as a 64-bit integer (Int64 or Int64u).

Core Usage

This method is the counterpart to the ValueInt64 setter. It is used to access the current value of a variable from the host application, typically after it has been manipulated by a uCalc expression or set programmatically.

using uCalcSoftware;

var uc = new uCalc();

// Define a 64-bit integer variable
var myId = uc.DefineVariable("myId As Int64");

// Set its value
myId.ValueInt64(9007199254740991);

// Retrieve its value using the type-safe getter
int64_t retrievedId = myId.ValueInt64();
Console.WriteLine($"Retrieved ID: {retrievedId}");

🆚 Comparative Analysis: Why Use a Type-Specific Getter?

While uCalc offers several ways to retrieve a variable's value, ValueInt64() is the best choice for 64-bit integers due to performance and data integrity.

1. ValueInt64() (Type-Safe Getter - Recommended)

   • Pros: Fastest method, returns the exact binary value without conversion, and preserves the full precision of 64-bit integers.
   • Cons: Specific to one data type.
   • Best for: Performance-critical code and handling large numbers like timestamps, database IDs, or financial calculations.

2. Value() (Generic Getter - Potential Precision Loss)

   • This method always returns a double. While convenient, a double only has about 15-17 decimal digits of precision. A 64-bit integer can have up to 19 digits. Using Value() on large Int64 values will result in precision loss.
   • Best for: General-purpose numeric retrieval where maximum precision is not critical.

3. ValueStr() (String-Based Getter)

   • This method returns the value as a string. It preserves precision but is slower due to the overhead of converting the number to a string and subsequent parsing if you need to use it as a number in your host application.
   • Best for: Displaying values or when a string representation is the desired final format.

In summary, always use ValueInt64() to retrieve Int64 or Int64u variables to guarantee both speed and data integrity.