HP SunSoft Pascal 4.0 - Manual (Page 115)

The C–Pascal Interface 91
6
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.
array array - Same as element type
variant record struct/union - -
fields in packed
record bit field - -
Table 6-2 C 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
Table 6-1 C and Pascal Size and Alignment of Compatible Types (Continued)
Pascal Type C Type Size (bytes) Alignment (bytes)