Info Catalog gdb: C gdb: C Constants

gdb: C Operators

 
 15.4.1.1 C and C++ Operators
 ............................
 
 Operators must be defined on values of specific types.  For instance,
 '+' is defined on numbers, but not on structures.  Operators are often
 defined on groups of types.
 
    For the purposes of C and C++, the following definitions hold:
 
    * _Integral types_ include 'int' with any of its storage-class
      specifiers; 'char'; 'enum'; and, for C++, 'bool'.
 
    * _Floating-point types_ include 'float', 'double', and 'long double'
      (if supported by the target platform).
 
    * _Pointer types_ include all types defined as '(TYPE *)'.
 
    * _Scalar types_ include all of the above.
 
 The following operators are supported.  They are listed here in order of
 increasing precedence:
 
 ','
      The comma or sequencing operator.  Expressions in a comma-separated
      list are evaluated from left to right, with the result of the
      entire expression being the last expression evaluated.
 
 '='
      Assignment.  The value of an assignment expression is the value
      assigned.  Defined on scalar types.
 
 'OP='
      Used in an expression of the form 'A OP= B', and translated to
      'A = A OP B'. 'OP=' and '=' have the same precedence.  The operator
      OP is any one of the operators '|', '^', '&', '<<', '>>', '+', '-',
      '*', '/', '%'.
 
 '?:'
      The ternary operator.  'A ? B : C' can be thought of as: if A then
      B else C.  The argument A should be of an integral type.
 
 '||'
      Logical OR.  Defined on integral types.
 
 '&&'
      Logical AND.  Defined on integral types.
 
 '|'
      Bitwise OR.  Defined on integral types.
 
 '^'
      Bitwise exclusive-OR.  Defined on integral types.
 
 '&'
      Bitwise AND.  Defined on integral types.
 
 '==, !='
      Equality and inequality.  Defined on scalar types.  The value of
      these expressions is 0 for false and non-zero for true.
 
 '<, >, <=, >='
      Less than, greater than, less than or equal, greater than or equal.
      Defined on scalar types.  The value of these expressions is 0 for
      false and non-zero for true.
 
 '<<, >>'
      left shift, and right shift.  Defined on integral types.
 
 '@'
      The GDB "artificial array" operator (Expressions
      Expressions.).
 
 '+, -'
      Addition and subtraction.  Defined on integral types,
      floating-point types and pointer types.
 
 '*, /, %'
      Multiplication, division, and modulus.  Multiplication and division
      are defined on integral and floating-point types.  Modulus is
      defined on integral types.
 
 '++, --'
      Increment and decrement.  When appearing before a variable, the
      operation is performed before the variable is used in an
      expression; when appearing after it, the variable's value is used
      before the operation takes place.
 
 '*'
      Pointer dereferencing.  Defined on pointer types.  Same precedence
      as '++'.
 
 '&'
      Address operator.  Defined on variables.  Same precedence as '++'.
 
      For debugging C++, GDB implements a use of '&' beyond what is
      allowed in the C++ language itself: you can use '&(&REF)' to
      examine the address where a C++ reference variable (declared with
      '&REF') is stored.
 
 '-'
      Negative.  Defined on integral and floating-point types.  Same
      precedence as '++'.
 
 '!'
      Logical negation.  Defined on integral types.  Same precedence as
      '++'.
 
 '~'
      Bitwise complement operator.  Defined on integral types.  Same
      precedence as '++'.
 
 '., ->'
      Structure member, and pointer-to-structure member.  For
      convenience, GDB regards the two as equivalent, choosing whether to
      dereference a pointer based on the stored type information.
      Defined on 'struct' and 'union' data.
 
 '.*, ->*'
      Dereferences of pointers to members.
 
 '[]'
      Array indexing.  'A[I]' is defined as '*(A+I)'.  Same precedence as
      '->'.
 
 '()'
      Function parameter list.  Same precedence as '->'.
 
 '::'
      C++ scope resolution operator.  Defined on 'struct', 'union', and
      'class' types.
 
 '::'
      Doubled colons also represent the GDB scope operator (
      Expressions Expressions.).  Same precedence as '::', above.
 
    If an operator is redefined in the user code, GDB usually attempts to
 invoke the redefined version instead of using the operator's predefined
 meaning.
 

Info Catalog gdb: C gdb: C Constants