Thanks for getting us back on topic - we could use some lateral thinking, or in-depth knowledge of C++, right now. Juha used to pop in at times like this, but I haven't seen him around for a while.

static const LOG_FLAGS x;

Should be in the class definition LOG_FLAGS, rather than inside LOG_FLAGS::init() ( but see later ** )

*this = x;

Won't then be needed, since static members are initialised with the class.

Other Notes on the patches over time:

• memset indeed has different implementation by compiler / libraries, and many old 'bog standard' buffer manipulation things from back in the day are now considered 'unsafe' (meaning unreliable for our purposes). That's mostly to do with security and thread safety, since there are ways break, or break into, buffer manipulation type things, so fair enough they decided to change its use.
  
• The static keyword has a different meaning inside a class definition. it's in the wrong place now, but when in the correct place in LOG_FLAGS definition it will just ensure there is one single LOGS_FLAGS structure, now matter how many times init is called.
  

Why isn't the code just put in

LOG_FLAGS::LOG_FLAGS() 

instead of

LOG_FLAGS::init()

?

• (**) creating a static LOG_FLAGS structure within LOG_FLAGS may also be problematic, because a circular definition like that may start a recursive initialisation thing.
• I would rename the existing flags structure definition to LOG_FLAGS_STRUCT (or similar), then create a LOG_FLAGS class with the static LOG_FLAGS_STRUCT as a member, alongside the constructor, init() and anything else rightly belonging within LOG_FLAGS that way LOG_FLAGS_STRUCT can be initialised once when the class is created (with zeroes), then tweaked in LOG_FLAGS::init() by putting:


x.task = true;
x.file_xfer = true;
x.sched_ops = true;

Would have been nice if LOG_FLAGS were defined in log_flags.h/.cpp , but whatever, found it in cc_config.
Needs some minor rejigging so as not to have to change references to log flags elsewhere in the client. Having a look

Simplest 'potential' fix I can think of, that won't require changing references to log_flags throughout the codebase. :

void LOG_FLAGS::init() {
	    static const LOG_FLAGS x;
	    *this = x;
                                                      // ...

becomes

static const LOG_FLAGS log_flag_defaults;

void LOG_FLAGS::init() {
	*this = log_flag_defaults;
                                                  // ...

With
static const LOG_FLAGS log_flag_defaults;

being outside of the class definition, it 'should' be initialised with zeroes (as originally intended, but inside that LOG_FLAGS class member init(), it means a different thing than whoever put it there thought.)

If still no-go, can nix that log_flag_defaults static definition, and go to the definition of LOG_FLAGS instead (in cc_config.cpp?)
each line would then need to be made static and = 0;
example, in cc_config,h instead of .cpp :

//initialising in the .h, each member separately ... On by default

static task = true;
static file_xfer = true;
static sched_ops = true;

// off
 by default; intended for developers and testers
	 
   //
	 
  static bool android_debug = false;
	 
       // show Android-specific info (battery etc.)
	 
   static bool app_msg_receive;
	 
       // show shared-mem message from apps
	 
   static bool app_msg_send;

Avoiding the need for some defaults structure and anything worthwhile in init(), But that would be too 'normal'.
Alternatively (also more 'normal', but admittedly labourious/error-prone) would be to initialise them in the constructor (LOG_FLAGS::LOG_FLAGS() ) one by one.

Jason:

Simplest 'potential' fix I can think of, that won't require changing references to log_flags throughout the codebase. :

void LOG_FLAGS::init() {
	    static const LOG_FLAGS x;
	    *this = x;
                                                      // ...

becomes

static const LOG_FLAGS log_flag_defaults;

void LOG_FLAGS::init() {
	*this = log_flag_defaults;
                                                  // ...

Fri 17 Apr 2020 16:57:41 BST |  | cc_config.xml not found - using defaults
Fri 17 Apr 2020 16:57:41 BST |  | Starting BOINC client version 7.16.6 for x86_64-pc-linux-gnu
Fri 17 Apr 2020 16:57:41 BST |  | log flags: file_xfer, sched_ops, task
...
Fri 17 Apr 2020 16:58:57 BST |  | Re-reading cc_config.xml
Fri 17 Apr 2020 16:58:57 BST |  | Config: GUI RPC allowed from any host
Fri 17 Apr 2020 16:58:57 BST |  | Config: GUI RPCs allowed from:
Fri 17 Apr 2020 16:58:57 BST |  | Config: don't check file sizes
Fri 17 Apr 2020 16:58:57 BST |  | Config: don't use VirtualBox
Fri 17 Apr 2020 16:58:57 BST |  | Config: event log limit 3000 lines
Fri 17 Apr 2020 16:58:57 BST |  | log flags: file_xfer, sched_ops, task, sched_op_debug, unparsed_xml

Well, Charlie has said some nice things about my proposed solution - but David is more interested in adding yet more new features than fixing the ones he broke. I despair sometimes.