Shared Library Changes for Release 1.2.0/1.2.1/1.2.2


This release contains a handful of changes, which affect backward compatibility. Consequently, the libddcutil SONAME is now The shared library name is libddcutil.4.3.0. In conformance with Debian practice, the package name is libddcutil4.

libddcutil trace file

libddcutil can redirect all output that it would normally be sent to the terminal to a trace file instead. The file is specified using option --libddcutil-trace-file. This option can be only be specified in the [libddcutil] section of the ddcutil configuration file, ddcutilrc. The file name given can be either absolute or relative. If relative, the directory is resolved as per the definition of XDG_STATE_HOME in the XDG specification. Typically this is $HOME/.local/state/ddcutil. This allows for tracing in situations where there is no terminal to which to write, e.g. PowerDevil in KDE Plasma.

API changes

Structs and Enums Comments
type DDCA_TRACE_OPTIONS  add value DDCA_TRCOPT_WALLTIME (release 1.2.1)

New Function Comments
ddca_add_trace_groups  Add to the set of traced groups
ddca_get_extended_version_string  Version string with optional suffix, e.g. "1.1.2-rc2"
ddca_redetect_displays  Redetect displays
ddca_get_display_refs  Returns a null-terminated list of valid DDCA_Display_Refs
ddca_get_display_info  Returns DDCA_Display_Info for a DDCA_Display_Ref


  • The existing API function ddca_set_trace_groups() replaces the existing set of trace groups, whereas new API function ddca_add_trace_groups() adds to the current set.
  • Calling ddca_get_display_refs() followed by calling ddca_get_display_info() for each display is preferred over ddca_get_display_info_list2(). Experience has shown that it leads to cleaner client code.

Changed Function Comments

New Macro Comments
DDCUTIL_VSUFFIX  version suffix, may be ""

Miscellaneous libddcutil changes

  • Additional checks are performed on DDCA_Display_Ref and DDCA_Display_Handle function arguments.
  • assert{} statements are used in libddcutil for situations that should be logically impossible. To aid in remote problem diagnosis, many of these statements have been replaced by macro TRACE_ASSERT(), which additionally writes a messsage to both the libddcutil trace log and the system log.
  • Recognize configuration file option --libddcutil-trace-file --library-trace-file