Guardian Procedure Calls Reference Manual

TAL Syntax for a Guardian Procedure Call
An example of the TAL syntax description used in this manual is shown in Figure 1-1.
Figure 1 Sample TAL Syntax for a Procedure Call
The numbered items in the diagram are described below:
This indicates that the procedure is a function procedure; it returns a value of the indicated type (in this case
INT) when referenced in an expression. You can specify the variable as retval, status, error^code
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or some other appropriate name in other function procedure calls. For function procedures that set the
condition code, you must declare the return variable as a simple variable. If you declare it as a subscripted
variable or a structure element, assigning a value to it can alter the condition code. "CALL" is a TAL CALL
statement. Any procedure that does not return a value must be invoked by a TAL CALL statement. In addition,
you can use a CALL statement to invoke a function procedure if you do not need the returned value.
This is the name of the procedure that is called. The name is not case-sensitive but otherwise must appear
in the program exactly as shown.
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You must enclose the list of parameters in parentheses. Use commas to separate parameters when there is
more than one. If you omit optional parameters, a placeholder comma (,) must be present for each omitted
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parameter unless you omit it from the end of the list. An optional parameter is indicated in a syntax diagram
by a parameter name enclosed in square brackets. Two parameters separated by a colon are treated as a
unit. If they are optional parameters, both members of the pair must be either present or absent. If you omit
the pair within a list of parameters, use only a single placeholder comma. In references to the ordinal numbers
of parameters, the pair is considered one parameter.
The exclamation point indicates that a comment follows. The comment can be an "i", an "o", or "i,o",
indicating that the parameter is either an input (i) parameter, an output (o) parameter, or both. In the example
shown, "i:i" indicates that nodename and length are both input parameters.
4
This line also indicates whether the parameter is an input parameter, an output parameter, or both. In the
example shown, "input:input" indicates that nodename and length are both input parameters.
5
This line indicates the parameter type. In the example shown, the types for nodename and length are
both given, separated by a comma. The possible parameter types include:
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16-bit integerINT
32-bit integerINT(32)
character string (eight-bit character)STRING
64-bit fixed-point numberFIXED
32-bit floating-point numberREAL
32-bit addressEXTADDR
For a complete discussion of formal parameter specifications, see the pTAL Reference Manual. The parameter
type is followed by a colon. Additional information after the colon includes:
means the actual value or contents of a parameter are passed.value
34 Introduction to Guardian Procedure Calls