dwarf_get_fde_instr_bytes(3) [freebsd man page]

DWARF_GET_FDE_INSTR_BYTES(3)				   BSD Library Functions Manual 			      DWARF_GET_FDE_INSTR_BYTES(3)

NAME

     dwarf_get_fde_instr_bytes -- retrieve instructions from FDE descritpor

LIBRARY

     DWARF Access Library (libdwarf, -ldwarf)

SYNOPSIS

     #include <libdwarf.h>

     int
     dwarf_get_fde_instr_bytes(Dwarf_Fde fde, Dwarf_Ptr *ret_inst, Dwarf_Unsigned *ret_len, Dwarf_Error *error);

DESCRIPTION

     Function dwarf_get_fde_instr_bytes() retrieves instruction bytes from a given FDE descriptor.

     Argument fde should reference a valid DWARF FDE descriptor.

     Argument ret_inst should point to a location that will be set to a pointer to an array of bytes containing the instructions of the FDE
     descriptor.

     Argument ret_len should point to a location that will hold the length in bytes of the instructions returned in argument ret_inst.

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

     Applications can use the function dwarf_expand_frame_instructions(3) to parse and expand the returned instruction bytes into an array of
     Dwarf_Frame_Op descriptors.

RETURN VALUES

     Function dwarf_get_fde_instr_bytes() returns DW_DLV_OK when it succeeds.  In case of an error, it returns DW_DLV_ERROR and sets the argument
     err.

ERRORS

     Function dwarf_get_fde_instr_bytes() can fail with:

     [DW_DLE_ARGUMENT]	One of the arguments fde, ret_inst or ret_len was NULL.

SEE ALSO

     dwarf(3), dwarf_expand_frame_instructions(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_list(3), dwarf_get_fde_list_eh(3), dwarf_get_fde_n(3), dwarf_get_fde_range(3)

BSD
								   May 23, 2011 							       BSD

DWARF_EXPAND_FRAME_INSTRUCTIONS(3)			   BSD Library Functions Manual 			DWARF_EXPAND_FRAME_INSTRUCTIONS(3)

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 instruction bytes into an array of Dwarf_Frame_Op descriptors.

     Argument cie should reference the CIE descriptor associated with the instructions 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 succeeds.  In case of an error, it returns DW_DLV_ERROR and sets the
     argument 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