HP SunSoft Pascal 4.0 Precautions with Compatible Types, Character Strings, C-Pascal Interface

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Table 6-1C and Pascal Size and Alignment of Compatible Types (Continued)

Pascal Type	C Type	Size (bytes)	Alignment (bytes)
array	array	-	Same as element type
variant record	struct/union	-	-
fields in packed	bit field	-	-
record
Table 6-2C and Pascal Size and Alignment of Compatible Types with –xl
Pascal Type	C Type	Size (bytes)	Alignment (bytes)
real	float	4	4
integer	short int	2	2

Precautions with Compatible Types

This section describes the precautions you should take when working with compatible types.

The shortreal Type

The Pascal shortreal and C float compatibility works if you pass by reference. See “Value Parameters” on page 112 for examples that show you how to pass by value.

Character Strings

C has several assumptions about strings. All C strings are:

•Passed by reference since C strings are arrays

•Terminated by a null byte

•Located in static variable storage

You can satisfy these assumptions as follows:

•Pass by reference by making the strings var, in, out, or in out parameters.

•Provide the null byte explicitly before passing a string to C. Pascal guarantees the null byte only if the string is a constant. The null byte is not required by the ISO Pascal Standard.

The C–Pascal Interface 91