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DWARF_EXPAND_FRAME_IN... BSD Library Functions Manual DWARF_EXPAND_FRAME_IN...

NAME
     dwarf_expand_frame_instructions --	expand frame instructions

LIBRARY
     DWARF Access Library (libdwarf, -ldwarf)

SYNOPSIS
     #include <libdwarf.h>

     int
     dwarf_expand_frame_instructions(Dwarf_Cie cie, Dwarf_Ptr instructions,
	 Dwarf_Unsigned	len, Dwarf_Frame_Op **ret_ops,
	 Dwarf_Signed *ret_opcnt, Dwarf_Error *error);

DESCRIPTION
     Function dwarf_expand_frame_instructions()	translates DWARF frame in-
     struction bytes into an array of Dwarf_Frame_Op descriptors.

     Argument cie should reference the CIE descriptor associated with the in-
     structions	to be translated.

     Arugment instructions should point	to an array of frame instruction
     bytes, as returned	by the functions dwarf_get_cie_info(3) or
     dwarf_get_fde_instr_bytes(3).

     Argument len should specify the number of the frame instruction bytes to
     be	translated.

     Argument ret_ops should point to a	location that will be set to a pointer
     to	an array of translated Dwarf_Frame_Op descriptors.

     Argument ret_opcnt	should point to	a location that	will hold the total
     number of the returned descriptors.

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

   Memory Management
     The memory	area used for the descriptor array returned in argument
     ret_ops is	allocated by DWARF Access Library (libdwarf, -ldwarf).	Appli-
     cation code should	use function dwarf_dealloc(3) with type
     DW_DLA_FRAME_BLOCK	to free	the memory area	when the descriptor array is
     no	longer needed.

RETURN VALUES
     Function dwarf_expand_frame_instructions()	returns	DW_DLV_OK when it suc-
     ceeds.  In	case of	an error, it returns DW_DLV_ERROR and sets the argu-
     ment err.

ERRORS
     Function dwarf_expand_frame_instructions()	can fail with:

     [DW_DLE_ARGUMENT]	One of the arguments cie, instructions,	ret_ops	or
			ret_opcnt was NULL.

     [DW_DLE_ARGUMENT]	Argument len was 0.

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

     [DW_DLE_FRAME_INSTR_EXEC_ERROR]
			An unknown instruction was found in the	instruction
			bytes provided in argument instructions.

EXAMPLE
     To	retrieve and expand the	frame instructions for a given FDE descriptor,
     use:

	   Dwarf_Dbg dbg;
	   Dwarf_Cie cie;
	   Dwarf_Fde fde;
	   Dwarf_Ptr fde_inst;
	   Dwarf_Unsigned fde_instlen;
	   Dwarf_Frame_Op *ops;
	   Dwarf_Signed	opcnt;
	   Dwarf_Error de;

	   /* ... assuming `dbg` references a valid DWARF debugging context,
	     `fde` references a	valid FDE descriptor and `cie` holds the CIE
	     descriptor	associated with	the FDE	descriptor ... */

	   if (dwarf_get_fde_instr_bytes(fde, &fde_inst, &fde_instlen,
	       &de) != DW_DLV_OK)
		   errx(EXIT_FAILURE, "dwarf_get_fde_instr_bytes failed: %s",
		       dwarf_errmsg(de));

	   if (dwarf_expand_frame_instructions(cie, fde_inst, fde_instlen,
	       &ops, &opcnt, &de) != DW_DLV_OK)
		   errx(EXIT_FAILURE,
		       "dwarf_expand_frame_instructions	failed:	%s",
		       dwarf_errmsg(de));

	   for (i = 0; i < opcnt; i++) {
		   /* ... use ops[i] ... */
	   }

	   /* Free the memory area when	no longer needed. */
	   dwarf_dealloc(dbg, ops, DW_DLA_FRAME_BLOCK);

SEE ALSO
     dwarf(3), dwarf_frame_instructions_dealloc(3), dwarf_get_cie_info(3),
     dwarf_get_cie_index(3), dwarf_get_cie_of_fde, dwarf_get_fde_at_pc(3),
     dwarf_get_fde_info_for_all_regs(3), dwarf_get_fde_info_for_all_regs3(3),
     dwarf_get_fde_info_for_cfa_reg3(3), dwarf_get_fde_info_for_reg(3),
     dwarf_get_fde_info_for_reg3(3), dwarf_get_fde_instr_bytes(3),
     dwarf_get_fde_list(3), dwarf_get_fde_list_eh(3), dwarf_get_fde_n(3)

BSD			       November	9, 2011				   BSD

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | EXAMPLE | SEE ALSO

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