Detecting CAPIE¶

A mod asks "is CAPIE here?" for three different reasons: to draw an indicator, to decide whether an effect may run, and to choose which editor to show. One signal cannot answer all three, because HOI4 keeps command data, saved data and drawn text apart. Mixing the signals up is the most likely source of bugs.

S1: localisation keys¶

capie_core.dll answers three keys whenever the game draws them. The SDK's localisation holds the fallbacks, which players see when CAPIE is missing:

Nest them in your own keys:

l_english:
 MY_MOD_CAPIE_LINE:0 "$CAPIE_STATUS$"

The mechanism works today: Rename Anything's RN_PLUGIN_STATUS key reads "CAPIE 1.0 loaded" with CAPIE and the mod's fallback without it, and nesting through $...$ works. Because the text is resolved when it is drawn, S1 is right immediately after loading a save without CAPIE.

S1 is text. A trigger cannot read it, so it cannot decide what a script does.

S2: the command record¶

When CAPIE is loaded, it adds capie_cap (the API level) to the Apply command of every grammar editor and removes any copy that came from elsewhere. capie_v1_begin reads it for you:

set_temp_variable = { capie_open_epoch = my_mod_epoch }
capie_v1_begin = yes
# capie_err = 10: CAPIE missing; 11: older than capie_min_api; 0: go on

Rename Anything uses the same pattern with its private record rn_native_cap and error code rn_pair_err = 10.

S2 tells you CAPIE is present on the machine that sent the command. It is not permission to act; check authority separately.

S3: the hint flag¶

GUI triggers run outside any command, so they cannot see S2. capie_v1_begin therefore notes the result on the acting country, through capie_v1_note_presence:

capie_v1_note_presence = {
    if = {
        limit = { check_variable = { temp_var:capie_cap > 0 } }
        ROOT = {
            set_variable = { capie_v1_ver = temp_var:capie_ver }
            set_country_flag = capie_v1_seen
        }
    }
    else = {
        ROOT = { clear_variable = capie_v1_ver clr_country_flag = capie_v1_seen }
    }
    capie_v1_mp_recompute = yes
}

The flag is saved with the game, so it can be wrong right after loading a save on a machine without CAPIE. That is acceptable only because a wrong hint can at worst show an editor whose Apply then fails cleanly with "CAPIE is not loaded. Nothing was changed." It must never lead to a wrong rename. The same values feed the multiplayer check.

Recipe¶

1. Every Apply effect starts with capie_v1_begin.
2. GUI visible triggers use S3 only to choose a layout.
3. Every effect that needs CAPIE stops when capie_err is not 0.
4. Indicators use S1.

Whether on_startup also fires when a save is loaded is not known. The recipe does not rely on it.