macpstr

Option Type	Default Value	#pragma options	C	C++
-qoption	nomacpstr	MACPSTR	x	x

Syntax

    -qmacpstr | -qnomacpstr 
    MACPSTR | NOMACPSTR

Purpose Converts Pascal string literals into null-terminated strings where the first byte contains the length of the string.

Notes A Pascal string literal always contains the characters "\p. The characters \p in the middle of a string do not form a Pascal string literal; the characters must be immediately preceded by the " (double quote) character.

The final length of the Pascal string literal can be no longer than 255 bytes (the maximum length that can fit in a byte).

For example, the -qmacpstr converts:

"\pABC"

to:

'\03' , 'A' , 'B' , 'C' , '\0'

The compiler ignores the -qmacpstr option when the -qmbcs or -qdbcs option is active because Pascal-string-literal processing is only valid for one-byte characters.

The #pragma options keyword MACPSTR is only valid at the top of a source file before any C or C++ source statements. If you attempt to use it in the middle of a source file, it is ignored and the compiler issues an error message.

Examples of Pascal String Literals The compiler replaces trigraph sequences by the corresponding single-character representation. For example:

"??/p pascal string"

becomes:

"\p pascal string"

The following are examples of valid Pascal string literals:

ANSI Mode

"\p pascal string"

Each instance of a new-line character and an immediately preceding backslash (\) character is deleted, splicing the physical source lines into logical ones. For example:

"\p pascal \
 string"

Two Pascal string literals are concatenated to form one Pascal string literal. For example:

"\p ABC" "\p DEF"

"\p ABC" "DEF"

becomes:

"\06ABCDEF"

For the macro ADDQUOTES:

#define ADDQUOTES (x) #x

where x is:

\p pascal string

\p pascal \
 string

becomes:

"\p pascal string"

Note however that:

ADDQUOTES(This is not a "\p pascal string")

becomes:

"This is not a \"\\p pascal string\""

Extended Mode

Is the same as ANSI mode, except the macro definition would be:

#define ADDQUOTES_Ext (x) "x"

Where x is the same as in the ANSI example:

\p pascal string
\p pascal \
 string

String Literal ProcessingThe following describes how Pascal string literals are processed.

Concatenating a Pascal string literal to a normal string gives a non-Pascal string. For example:
```
    "ABC" "\pDEF"
```
gives:
```
    "ABCpDEF"
```
A Pascal string literal cannot be concatenated with a wide string literal.
The compiler truncates a Pascal string literal that is longer than 255 bytes (excluding the length byte and the terminating NULL) to 255 characters.
The compiler ignores the -qmacpstr option if -qmbcs or -qdbcs is used, and issues a warning message.
Because there is no Pascal-string-literal processing of wide strings, using the escape sequence \p in a wide string literal with the -qmacpstr option, generates a warning message and the escape sequence is ignored.
The Pascal string literal is not a basic type different from other C or C++ string literals. After the processing of the Pascal string literal is complete, the resulting string is treated the same as all other strings. If the program passes a C string to a function that expects a Pascal string, or vice versa, the behavior is undefined.
Concatenating two Pascal string literals, for example, strcat(), does not result in a Pascal string literal. However, as described above, two adjacent Pascal string literals can be concatenated to form one Pascal string literal in which the first byte is the length of the new string literal.
Modifying any byte of the Pascal string literal after the processing has been completed does not alter the original length value in the first byte.
No errors or warnings are issued when the bytes of the processed Pascal string literal are modified.
Entering the characters:
```
    '\p' , 'A' , 'B' , 'C' , '\0'
```
into a character array does not form a Pascal string literal.

Example To compile mypascal.c and convert string literals into null-terminated strings, enter:

xlC mypascal.c -qmacpstr

List of Compiler Options and Their Defaults