dwarf_new_expr(3) [freebsd man page]

DWARF_NEW_EXPR(3)					   BSD Library Functions Manual 					 DWARF_NEW_EXPR(3)

NAME

     dwarf_new_expr -- create a location expression descriptor

LIBRARY

     DWARF Access Library (libdwarf, -ldwarf)

SYNOPSIS

     #include <libdwarf.h>

     Dwarf_P_Expr
     dwarf_new_expr(Dwarf_P_Debug dbg, Dwarf_Error *err);

DESCRIPTION

     Function dwarf_new_expr() allocates a DWARF location expression descriptor used to build up a location expression stream.

     The application can use the functions dwarf_add_expr_gen(3) and dwarf_add_expr_addr_b(3) to add location expression operators to the created
     descriptor.  When done, the application can call the function dwarf_expr_into_block(3) to retrieve the generated byte stream for the location
     expression, or call the function dwarf_add_AT_location_expr(3) to create an attribute with the location expression stream as its value.

     Argument dbg should reference a DWARF producer instance allocated using dwarf_producer_init(3) or dwarf_producer_init_b(3).

     If argument err is not NULL, it will be used to store error information in case of an error.

RETURN VALUES

     On success, function dwarf_new_expr() returns the created location expression descriptor.	In case of an error, function dwarf_new_expr()
     returns DW_DLV_BADADDR and sets the argument err.

ERRORS

     Function dwarf_new_expr() can fail with:

     [DW_DLE_ARGUMENT]	Argument dbg was NULL.

     [DW_DLE_MEMORY]	An out of memory condition was encountered during the execution of the function.

EXAMPLES

     To create a location expression descriptor, add location expression operators to it and to retrieve the generated byte stream, use:

	   Dwarf_P_Debug dbg;
	   Dwarf_Error de;
	   Dwarf_P_Expr pe;
	   Dwarf_Addr buf;
	   Dwarf_Unsigned len;

	   /* ...Assume that `dbg' refers to a DWARF producer instance... */

	   if ((pe = dwarf_new_expr(dbg, &de)) == DW_DLV_BADADDR) {
		   warnx("dwarf_new_expr failed: %s", dwarf_errmsg(-1));
		   return;
	   }

	   if (dwarf_add_expr_gen(pe, DW_OP_regx, 55, 0, &de) ==
	       DW_DLV_NOCOUNT) {
		   warnx("dwarf_add_expr_gen failed: %s", dwarf_errmsg(-1));
		   return;
	   }

	   if ((buf = dwarf_expr_into_block(pe, &len, &de)) ==
	       DW_DLV_BADADDR) {
		   warnx("dwarf_expr_into_block failed: %s",
		       dwarf_errmsg(-1));
		   return;
	   }

SEE ALSO

     dwarf(3), dwarf_add_AT_location_expr(3), dwarf_add_expr_gen(3), dwarf_add_expr_addr(3), dwarf_add_expr_addr_b(3),
     dwarf_expr_current_offset(3), dwarf_expr_into_block(3), dwarf_producer_init(3), dwarf_producer_init_b(3)

BSD
								 September 8, 2011							       BSD

Check Out this Related Man Page

DWARF_ADD_AT_SIGNED_CONST(3)				   BSD Library Functions Manual 			      DWARF_ADD_AT_SIGNED_CONST(3)

NAME

     dwarf_add_AT_signed_const, dwarf_add_AT_unsigned_const -- create and attach constant class attributes

LIBRARY

     DWARF Access Library (libdwarf, -ldwarf)

SYNOPSIS

     #include <libdwarf.h>

     Dwarf_P_Attribute
     dwarf_add_AT_signed_const(Dwarf_P_Debug dbg, Dwarf_P_Die die, Dwarf_Half attr, Dwarf_Signed value, Dwarf_Error *err);

     Dwarf_P_Attribute
     dwarf_add_AT_unsigned_const(Dwarf_P_Debug dbg, Dwarf_P_Die die, Dwarf_Half attr, Dwarf_Unsigned value, Dwarf_Error *err);

DESCRIPTION

     These functions create attribute descriptors belonging to the 'constant' class and attach them to the debugging information entry referenced
     by argument die.

     Argument dbg should reference a DWARF producer instance allocated using dwarf_producer_init(3) or dwarf_producer_init_b(3).

     Argument die should reference a debugging information entry allocated using dwarf_new_die(3).

     Argument attr specifies the attribute code of the created attribute descriptor.

     Function dwarf_add_AT_signed_const() creates an attribute descriptor with the signed value specified in argument value.

     Function dwarf_add_AT_unsigned_const() creates an attribute descriptor with the unsigned value specified in argument value.

     The attribute created by these function will have one of the DWARF forms DW_FORM_data1, DW_FORM_data2, DW_FORM_data4 or DW_FORM_data8,
     depending on the size of the value specified in argument value.

     If argument err is not NULL, it will be used by these functions to store error information in case of an error.

RETURN VALUES

     On success, these functions return the created attribute descriptor.  In case of an error, these functions return DW_DLV_BADADDR and set the
     argument err.

ERRORS

     These functions can fail with:

     [DW_DLE_ARGUMENT]	Either of the arguments dbg or die was NULL.

     [DW_DLE_MEMORY]	An out of memory condition was encountered during execution.

SEE ALSO

     dwarf(3), dwarf_add_AT_const_value_signedint(3), dwarf_add_AT_const_value_unsignedint(3), dwarf_add_AT_dataref(3),
     dwarf_add_AT_ref_address(3), dwarf_add_AT_targ_address_b(3), dwarf_new_die(3), dwarf_producer_init(3), dwarf_producer_init_b(3)

BSD
								 September 4, 2011							       BSD

Linux and UNIX Man Pages

dwarf_new_expr(3) [freebsd man page]

Check Out this Related Man Page