Magnetometer calibration is saved/read using locale-dependent functions

[nitsch]

    i get this message in my CECH-ZCM1E unit

    [PSMOVE CRITICAL] Assertion fail in psmove_load_magnetometer_calibration: result == 3

    is ok?

    greetings

Originally posted by @sl1pkn07 in #372 (comment)

[nitsch]

It means that there were problems reading the calibration data that was written to a file previously. Can you share the calibration file for closer inspection?

The file is named xx_xx_xx_xx_xx_xx.magnetometer.csv (with your controller's BDADDR substituted for the xx) and should be located inside the .psmoveapi directory below your home directory.

[sl1pkn07]

ok, i thik i found the problem

if launch the demos/labs/etc with my locale (LANG=es_ES.UTF-8) fails with the message posted above. but if launch with LC_ALL=C or LANG=C, the message is gone

└───╼  locale
LANG=es_ES.UTF-8
LC_CTYPE="es_ES.UTF-8"
LC_NUMERIC="es_ES.UTF-8"
LC_TIME="es_ES.UTF-8"
LC_COLLATE="es_ES.UTF-8"
LC_MONETARY="es_ES.UTF-8"
LC_MESSAGES="es_ES.UTF-8"
LC_PAPER="es_ES.UTF-8"
LC_NAME="es_ES.UTF-8"
LC_ADDRESS="es_ES.UTF-8"
LC_TELEPHONE="es_ES.UTF-8"
LC_MEASUREMENT="es_ES.UTF-8"
LC_IDENTIFICATION="es_ES.UTF-8"
LC_ALL=

the file: 00_06_f7_d2_d8_36.magnetometer.csv

greetings

[thp]

Alright, this is because fscanf() used in psmove_load_magnetometer_calibration() and fprintf() used in psmove_save_magnetometer_calibration() are locale-dependent (LC_NUMERIC).

However, the command-line tools (e.g. the calibration tool) don't set the locale (hence the . in the file), but the GUI toolkits usually set it (hence the , expected by *scanf functions).

Some things that you could test:

1. Only setting LC_NUMERIC="C" + launching the GUI tools
2. Adding the following call in psmove_init()

diff --git a/src/psmove.c b/src/psmove.c
index f5db775..44c0eed 100644
--- a/src/psmove.c
+++ b/src/psmove.c
@@ -327,6 +327,8 @@ psmove_get_half_frame(PSMove *move, enum PSMove_Sensor sensor,
 enum PSMove_Bool
 psmove_init(enum PSMove_Version version)
 {
+    setlocale(LC_NUMERIC, "C");
+
     // Compile-time version of the library is PSMOVE_CURRENT_VERSION
     // Compile-time version of the user code is the value of "version"
 

As the locale affects all of the program, it's not ideal, as it means any program pulling in PS Move API would suddenly see numeric value with "." unconditionally, independent of locale. One option would be to use newlocale() + uselocale() just around the *scanf() and *printf() calls and restore the locale again after those calls. This is basically what macOS (+*BSD's) *scanf_l() functions provide (unfortuntely, those don't seem to be available in glibc).

See also: https://stackoverflow.com/a/13919957/1047040

[thp]

Proposed PR in #453, @sl1pkn07 please give it a try if it fixes the issue for you.

[sl1pkn07]

yes. #453 seems fixed my problem. the message is gone. and seems fixed a calibration problem, after the PR, i get this message when launch the paint lab (for example)

[PSMOVE WARNING] Only 7/9 fields read from magnetometer calibration, discarding values. Please recalibrate.

after the recalibration, all OK

greetings