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$Id: dwarf_get_macro_details.3 2071 2011-10-27 03:20:00Z jkoshy $
.Dd March 20, 2011 .Os .Dt DWARF_GET_MACRO_DETAILS 3 .Sh NAME .Nm dwarf_get_macro_details .Nd retrieve macro information .Sh LIBRARY .Lb libdwarf .Sh SYNOPSIS n libdwarf.h .Ft int .Fo dwarf_get_macro_details .Fa "Dwarf_Debug dbg" .Fa "Dwarf_Off offset" .Fa "Dwarf_Unsigned max_count" .Fa "Dwarf_Signed *entry_cnt" .Fa "Dwarf_Macro_Details **details" .Fa "Dwarf_Error *err" .Fc .Sh DESCRIPTION Function .Fn dwarf_get_macro_details retrieves information about macros associated with a DWARF debug context. Information about macro entries are returned as an array of descriptors of type .Vt Dwarf_Macro_Details , with each .Vt Dwarf_Macro_Details descriptor describing one macro information entry.
p Argument .Ar dbg should reference a DWARF debug context allocated using .Xr dwarf_init 3 . Argument .Ar offset is an offset, relative to the .Dq ".debug_macinfo" section, to the start of the desired macro information. Argument .Ar max_count specifies the maximum number of macro information entries to be returned, or 0 if all entries are to be returned. Argument .Ar entry_cnt should point to a location that will be set to the number of entries actually returned. Argument .Ar details should point to a location that will be set to a pointer to an array of .Vt Dwarf_Macro_Details descriptors. If argument .Ar err is not NULL, it will be used to store error information in case of an error.
p .Vt Dwarf_Macro_Details descriptors are defined in the header file n libdwarf.h , and consist of the following fields: l -tag -width ".Va dmd_fileindex" -compact t Va dmd_offset The section-relative offset within the .Dq ".debug_macinfo" section of the macro information entry being described. t Va dmd_type The type code of this macro information entry; one of the .Dv DW_MACINFO_* constants defined by the DWARF specification. t Va dmd_lineno The line number associated with the macro information entry, or 0 if there is no applicable line number. t Va dmd_fileindex The source file index for the macro information entry. This field is only meaningful when .Va dmd_type field is set to .Dv DW_MACINFO_start_file . t Va dmd_macro The contents of this field is a pointer to a NUL-terminated string whose meaning depends on the value of the .Va dmd_type field: l -tag -width ".Dv DW_MACINFO_vendor_ext" -compact t Dv DW_MACINFO_define The returned string contains the macro name and value. t Dv DW_MACINFO_undef The string holds the macro name. t Dv DW_MACINFO_vendor_ext The .Va dmd_macro field points to a vendor defined string. .El The field is NULL for other values of .Va dmd_type . .El .Ss Memory Management The memory area used for the array of .Vt Dwarf_Macro_Details descriptors returned in argument .Ar details is owned by the .Lb libdwarf . The application should not attempt to directly free this pointer. Portable code should instead use .Fn dwarf_dealloc with the allocation type .Dv DW_DLA_STRING to indicate that the memory may be freed. .Sh RETURN VALUES Function .Fn dwarf_get_macro_details returns .Dv DW_DLV_OK when it succeeds. It returns .Dv DW_DLV_NO_ENTRY if there is no more macro information at the specified offset .Ar offset . In case of an error, it returns .Dv DW_DLV_ERROR and sets the argument .Ar err . .Sh ERRORS Function .Fn dwarf_get_macro_details can fail with: l -tag -width ".Bq Er DW_DLE_NO_ENTRY" t Bq Er DW_DLE_ARGUMENT One of the arguments .Ar dbg , .Ar entry_cnt or .Ar details was NULL. t Bq Er DW_DLE_NO_ENTRY There is no more macro information at the specified offset .Ar offset . .El .Sh EXAMPLE To loop through all the macro information entries associated with a DWARF debug context: d -literal -offset indent Dwarf_Debug dbg; Dwarf_Unsigned offset; Dwarf_Signed cnt; Dwarf_Macro_Details *md; Dwarf_Error de; offset = 0; while (dwarf_get_macro_details(dbg, offset, 0, &cnt, &md, &de) == DW_DLV_OK) { for (i = 0; i < cnt; i++) { /* Access fields of md[i] ... */ } offset = md[cnt - 1].dmd_offset + 1; } .Ed .Sh SEE ALSO .Xr dwarf 3 , .Xr dwarf_dealloc 3 , .Xr dwarf_find_macro_value_start 3 , .Xr dwarf_init 3