Statement LOCAL Foundation
Declaration and initialization of LOCAL variables.
LOCAL <VarName> [[:= <Expression>], ... ]
LOCAL <VarName> AS STRUCTURE <StructName>
The LOCAL statement declares memory variables of storage class LOCAL. Memory variables exist only in memory and are released after the end of a program, as opposed to field variables that are stored on disk. Storage classes define the lifetime and the visibility of variables. LOCAL variables are visible only within the function or procedure in which they are declared. They are released as soon as the function or procedure ends. Since their visibility is limited to the declaring function, they are not visible in any called functions or procedures. This also pertains to instances when a function calls itself (recursion). LOCAL variables are redeclared and initialized with each call of a function or procedure.
The LOCAL statement must precede all executable statements in a function or procedure, including the statements PRIVATE, PUBLIC and PARAMETERS. The variable name <VarName> can occur only once within a function. This includes variables which are declared as STATIC or MEMVAR. If a PRIVATE or PUBLIC variable of the name <VarName> already exists in a function, the PRIVATE or PUBLIC variable is "hidden" and is no longer visible within the function or procedure in which the LOCAL variable is declared.
The length of a variable name is unlimited, but only the first 255 characters are significant. A variable name consists of alphanumeric characters, and the first character may not be numeric. The underscore (_) is permitted as a special character.
A LOCAL variable can be initialized with the declaration, meaning the value of any legal expression may be assigned to it using the inline assignment operator (:=), or it can be initialized by use of the array element operator () as an array with any dimension and size you want.
By using the AS STRUCTURE syntax, a LOCAL variable can be initialized with a structure instance. This instance can then be accessed using the LOCAL reference, for example, for assigning values to structure members or for passing the stucture to an API function via the EXTERN command. See the STRUCTURE statement for more information.
If no assignment is made, LOCAL variables have the value NIL after declaration. When they are initialized as an array, no further assignment is possible and all array elements contain the value NIL.
LOCAL variables normally have the same lifetime as the function in which they are declared. However, they can also exist after a function ends if they are used in a code block defined in the declared function which is then returned from the function. In this case, a LOCAL variable exists within the code block and is detached from the declaring function (a detached local).
LOCAL variables cannot be saved in a file with the SAVE command. This can only be done with PRIVATE and PUBLIC variables.
The macro operator (&) cannot compile an expression containing a character string declared as a LOCAL variable. The reason is that LOCAL variables are resolved at compile time and their symbolic names do not exist at runtime.
The data type of LOCAL variables can be determined only with the function Valtype() and not with the function Type(). The reason is that the function Type() uses the macro operator in order to determine the data type of a variable or an expression. A character string must always be passed to the function Type(). Valtype() establishes the data type of a value.
In order to be able to track LOCAL variables in the debugger, the source code files (PRG files) must be compiled with the /B compiler switch so that the names of the LOCAL variables remain available as debug information.
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