Next: Symbol Tables, Previous: Types, Up: Top [Contents][Index]
This section describes the stabs support for macro define and undefine information, supported on some systems. (e.g., with -g3 -gstabs when using GCC).
A #define macro-name macro-body is represented with
an N_MAC_DEFINE stab with a string field of
macro-name macro-body.
An #undef macro-name is represented with an
N_MAC_UNDEF stabs with a string field of simply
macro-name.
For both N_MAC_DEFINE and N_MAC_UNDEF, the desc field is
the line number within the file where the corresponding #define
or #undef occurred.
For example, the following C code:
    #define NONE	42
    #define TWO(a, b)	(a + (a) + 2 * b)
    #define ONE(c)	(c + 19)
    main(int argc, char *argv[])
    {
      func(NONE, TWO(10, 11));
      func(NONE, ONE(23));
    #undef ONE
    #define ONE(c)	(c + 23)
      func(NONE, ONE(-23));
      return (0);
    }
    int global;
    func(int arg1, int arg2)
    {
      global = arg1 + arg2;
    }
produces the following stabs (as well as many others):
    .stabs	"NONE 42",54,0,1,0
    .stabs	"TWO(a,b) (a + (a) + 2 * b)",54,0,2,0
    .stabs	"ONE(c) (c + 19)",54,0,3,0
    .stabs	"ONE",58,0,10,0
    .stabs	"ONE(c) (c + 23)",54,0,11,0
NOTE: In the above example, 54 is N_MAC_DEFINE and
58 is N_MAC_UNDEF.