Debugging with GDB: M2 Constants

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15.4.9.3 Constants

GDB allows you to express the constants of Modula-2 in the following ways:

• Integer constants are simply a sequence of digits. When used in an expression, a constant is interpreted to be type-compatible with the rest of the expression. Hexadecimal integers are specified by a trailing ‘H’, and octal integers by a trailing ‘B’.
• Floating point constants appear as a sequence of digits, followed by a decimal point and another sequence of digits. An optional exponent can then be specified, in the form ‘E[+|-] nnn ’, where ‘ [+|-] nnn ’ is the desired exponent. All of the digits of the floating point constant must be valid decimal (base 10) digits.
• Character constants consist of a single character enclosed by a pair of like quotes, either single (') or double ("). They may also be expressed by their ordinal value (their ASCII value, usually) followed by a ‘C’.
• String constants consist of a sequence of characters enclosed by a pair of like quotes, either single (') or double ("). Escape sequences in the style of C are also allowed. See C and C++ Constants, for a brief explanation of escape sequences.
• Enumerated constants consist of an enumerated identifier.
• Boolean constants consist of the identifiers TRUE and FALSE.
• Pointer constants consist of integral values only.
• Set constants are not yet supported.