| .DECLARE (BASIC Procedure) Statement Details. |
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| DECLARE (BASIC Procedure) Statement Details |
|
| Syntax |
| DECLARE {FUNCTION | SUB } name [([parameterlist])] |
| |
| Argument Description |
| name The procedure's name. The name is limited to 40 |
| characters. FUNCTION names can end in one of the |
| type-declaration characters (%, &, !, #, or $) to |
| indicate the type of value returned. |
| |
| parameterlist A list of parameters indicating the number and |
| type of arguments used when calling the procedure. |
| Syntax is shown below. Only the number and type of |
| the arguments are significant. |
| |
| For calls within BASIC, the DECLARE statement is required only if you |
| call SUB procedures without the CALL keyword, or if you invoke a |
| FUNCTION defined in another module. |
| |
| A DECLARE statement also causes the compiler to check the number and |
| type of arguments used to invoke the procedure. QuickBASIC |
| automatically generates DECLARE statements when you save your program |
| while working in the environment. The DECLARE statement can appear |
| only in module-level code (not in a SUB or FUNCTION) and affects the |
| entire module. |
| |
| The parameterlist serves as a prototype for checking the number |
| and type of the arguments in SUB and FUNCTION calls. It has the |
| following syntax: |
| |
| variable[AS type][,variable[AS type]]... |
| |
| A variable is any valid BASIC variable name. If the variable is an |
| array, it may be followed by the number of dimensions in parentheses: |
| |
| DECLARE SUB DisplayText (A(2) AS STRING) |
| DIM Text$(100,5) |
| . |
| . |
| . |
| CALL DisplayText(Text$()) |
| |
| The number of dimensions is optional. |
| |
| The type is either INTEGER, LONG, SINGLE, DOUBLE, STRING, or a |
| user-defined type. Again, only the number and types of arguments are |
| significant. |
| |
| Note: You cannot have fixed-length strings in DECLARE statements |
| because only variable-length strings can be passed to SUB |
| and FUNCTION procedures. Fixed-length strings can appear |
| in an argument list but are converted to variable-length |
| strings before being passed. |
| |
| A variable's type can also be indicated by including an explicit type |
| character ( %, &, !, #, or $) or by relying on the default type. |
| |
| The form of the parameter list determines whether or not argument |
| checking is done, as shown in the following list: |
| |
| Declaration Meaning |
| |
| DECLARE SUB First You may only omit the parentheses |
| if the SUB or FUNCTION is separately |
| compiled. No argument checking is |
| done. |
| |
| DECLARE SUB First () First has no parameters. Arguments |
| in a CALL to First are flagged as |
| an error. An empty parameter list |
| indicates that the SUB or FUNCTION |
| has no parameters. |
| |
| DECLARE SUB First (X AS LONG) First has one long-integer |
| parameter. The number and type of |
| the arguments in each CALL or |
| invocation are checked when the |
| parameter list appears in the |
| DECLARE. |
