santileortiz

gprof

Prints a report containing time spent in each function. Also prints a report on the call graph by
telling for each function how many times was called and by whom, and also how many times it called
each other function.

1. Compile with flag -pg and optimizations.
2. Run executable, file gmon.out will be created.
3. Run $ gprof <path to binary>

santileortiz

The Liang-Barsky algorithm is a cheap way to find the intersection points between a line segment and an axis-aligned rectangle. It's a simple algorithm, but the resources I was pointed to didn't have particularly good explanations, so I tried to write a better one.

Consider a rectangle defined by x_min ≤ x ≤ x_max and y_min ≤ y ≤ y_max, and a line segment from (x_0, y_0) to (x_0 + Δ_x, y_0 + Δ_y). We'll be assuming at least one of Δ_x and Δ_y is nonzero.

(I'm working with Flash, so I'll be using the convention that y increases as you go down.)

We want to distinguish between the following cases:

santileortiz

gnome_session=$(pgrep --full -u $USER gnome-session-binary.*ubuntu)
eval export $(sed 's/\o000/\n/g;' < /proc/$gnome_session/environ | grep DISPLAY)
eval export $(sed 's/\o000/\n/g;' < /proc/$gnome_session/environ | grep XAUTHORITY)
eval export $(sed 's/\o000/\n/g;' < /proc/$gnome_session/environ | grep XDG_SESSION_TYPE)
eval export $(sed 's/\o000/\n/g;' < /proc/$gnome_session/environ | grep DBUS_SESSION_BUS_ADDRESS)

santileortiz

Compiled libraries from Gtk's Git repositoriy will end up inside <gtk repo>/gtk/.libs/. To run an application with these
libraries use:

LD_LIBRARY_PATH=<git repo>/gtk/.libs/ <app>

I normally call it from inside the repository using

LD_LIBRARY_PATH=./gtk/.libs/ ~/<app path>

NOTE: Gtk moved from Autotools to Meson, maybe this will put resulting libraries somewhere else.

santileortiz

The syntax for setting up a third level key in a .xkb file seems to be vey
picky, I still need to explore more xkbcomp's source code to know how things
work.

I noticed this because recently the way I used to define the AltGr key in my
custom layout stopped working. I'm not sure which commit in which project
caused this to stop working, could have been libxkbcommon (xkbcomp), xserver,
Gdk among others. What I do know is that suddenly pressing AltGr would set
GDK_MOD1_MASK in the received key release event. This modifier is treated by
Gdk (Together with GDK_CONTROL_MASK) as one that will NEVER serve to translate

santileortiz

Current (unresolved) keymap file
================================

The following command prints one include statement for each component of the
current keymap:

   $ setxkbmap -print
   
Note that this is not a resolved keymap file!. Quite the opposite, it shows
what will be passed to xkbcomp as components so that it resolves them to an

santileortiz

Information on how to create a custom layout
https://medium.com/@damko/a-simple-humble-but-comprehensive-guide-to-xkb-for-linux-6f1ad5e13450
https://github.com/damko/xkb_kinesis_advantage_dvorak_layout

Information about the RMLVO configuration format and syntax of the 'rules' file
http://who-t.blogspot.com/2008/09/rmlvo-keyboard-configuration.html

Very detailed description of how to configure XKB, it includes information about the syntax of .xkb files.
https://www.charvolant.org/doug/xkb/html/xkb.html

santileortiz

When using GTree I made the mistake of keeping pointers to keys and overwriting
them. I expected this would only affect the overwritten keys, and make lookups
for them return NULL. What actually happened was that other keys not related to
these became unaccessible. I am puzzled as to why this happened, it may be
interesting to dig inside GTree's implementation and see what's going on.

My guess is doing this breaks the sorted invariant of the tree, then things
will go crazy next time it tries to balance it, maybe for some reason it tries
to fix it by replacing existing keys?. Or, maybe the result of the string
comparison function does not really check for equallity, and instead has an

santileortiz

// This is a way of executing a different macro based on the number of argument
// passed to a macro with variable arguments. Essentially this is a way of
// executing macros conditionally even though C doesn't support using #if inside
// a macro definition.
//
// Source: https://stackoverflow.com/questions/3046889/optional-parameters-with-c-macros

// The multiple macros that you would need anyway [as per: Crazy Eddie]
#define XXX_0()                     <code for no arguments> 
#define XXX_1(A)                    <code for one argument> 

santileortiz

SELECT ?code ?countryLabel ?coordinates WHERE
{
  ?country wdt:P31 wd:Q3624078 ;
           p:P625 ?location .
  #not a former country
  FILTER NOT EXISTS {?country wdt:P31 wd:Q3024240}
  #and no an ancient civilisation (needed to exclude ancient Egypt)
  FILTER NOT EXISTS {?country wdt:P31 wd:Q28171280}
  
  # This doesn't bring all countries. It misses Armenia for example.