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Pascal and DOMAIN Pascal

B


This Appendix describes the differences between Pascal and Apollo DOMAIN Pascal, and how the -xl option can be used to get around most of these differences.


The -xl Option

The -xl option to the pc command makes the language accepted by the Pascal compiler similar to DOMAIN Pascal. Table B-1 lists the differences in your program when you compile it with and without the -xl option.

Table  B-1 Differences Between Programs Compiled with and without -xl  

With -xl
Without -xl

The default integer size is 16 bits.

The default is 32 bits.

The default real size is 32 bits.

The default is 64 bits.

The default enumerated type size is 16 bits.

The default is either 8 or 16 bits, depending on the number of elements in the enumerated set.

The source file is run through the preprocessor cppas before it is processed by the compiler.

The source file is run through the preprocessor cpp.

Pascal supports nonpascal as a routine option.

nonpascal is not supported.

The -L option, which maps all identifiers to lowercase, is on by default.

-L is off by default.

If the value of the expression in a case statement does not match any of the case values, the program falls through and does not generate an error. The program continues execution in the statement immediately following the case statement.

The compiler generates an error and halts.

The writing of enumerated and boolean variables defaults to uppercase and 15-character width format.

Enumerated variables default to the length of the type. boolean variables default to the length of true or false.

Integer or real constant literals that overflow implementation limits do not cause an error. The resulting action is undefined.

An error is generated.

No warning is generated when the argument to the addr function is a local or private variable.

A warning is generated.

Top-level variables, procedures, and functions in programs default to private.

Variables, procedures, and functions in programs default to public.

Top-level variables in modules default to private.

Variables in modules default to public.

Modules compiled with -xl are not compatible with modules compiled without -xl.

These two types of modules are not linked together.


DOMAIN Pascal Features Accepted but Ignored

Pascal accepts these DOMAIN Pascal features, but otherwise ignores them, with a warning message as appropriate:


DOMAIN Pascal Features Not Supported

Pascal does not support the following features of DOMAIN Pascal:


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