MSFS20 WASM I/O error

[mariomotta]

despite is written in SDK:

In order to access files from within an add-on, filenames can be prefixed in two ways:
".\": to access the files from within the add-on package. This has a read-only access.
"\work": to access a persistent storage that the add-on can use. This is a read/write access.

this piece of code:

FILE* fh = fopen (".\\default.ln3", "r");

  if (fh == (FILE*) 0) {
      fprintf(stderr,
          "SIM SKUNK WORKS G-91 DEBUG: failed to open .ln3 file errno:%d\n", errno);
      perror("fopen() failed");
      return (char*)0;
  }

produces a I/O error (errno = 29)

from sim console:
SIM SKUNK WORKS G-91 DEBUG: SimConnect connection open: OK
SIM SKUNK WORKS G-91 DEBUG: failed to open .ln3 file errno:29
fopen() failed : I/O error

error 29 is reported as: ESPIPE not valid search
any clue ?
thanks in advance
Mario

 

[DragonflightDesign]

Just a guess: try using fopen_s. fopen was deprecated quite a while a go but is still in use (guilty.... )

 

[WarpD]

Error 29 is an invalid seek.

 

[mariomotta]

Just a guess: try using fopen_s. fopen was deprecated quite a while a go but is still in use (guilty.... )

thanks, however fopen_s not recognized in c_lang :-(

 

[mariomotta]

Error 29 is an invalid seek.

thanks,
i don't see any reason for the invalid seek, the file does exists and is also in layout.json then should be set into VFS..
BTW:
i wrote on MSFS Forums, the answer was to read SDK
Holy crap :-(

 

[ErnieAlston]

If the file is in your top level package folder try just a single backslash, or no dot backslash

fh = fopen (".\default.ln3", "r");

fh = fopen ("default.ln3", "r");

 

[Prepar3DGuy]

Both FILE* fh = fopen(".\\default.ln3", "r"); and FILE* fh = fopen("./default.ln3", "r"); works without errors with your code, Mario.

Are you really sure, that file default.ln3 exists inside add-on package directory? Not directory where wasm module resides.
I have tested your code inside GaugeAircraft example from SDK. That example already loads fonts, images files from Data folder. And data folder have copied to package folder and have path to load (example for fonts) nvgCreateFont(nvgctx, "serif", "./data/Roboto-Regular.ttf");
File default.ln3 was placed inside add-on package directory C:\MSFS SDK\Samples\GaugeAircraft\Packages\mycompany-aircraft-wasm-gauge

 

[DragonflightDesign]

thanks, however fopen_s not recognized in c_lang :-(

Uh? fopen_s has been in C since the C11 standard of 2011. The current standard is C17 and it's definately in that.

 

[mariomotta]

Thanks a lo

Both FILE* fh = fopen(".\\default.ln3", "r"); and FILE* fh = fopen("./default.ln3", "r"); works without errors with your code, Mario.

Are you really sure, that file default.ln3 exists inside add-on package directory? Not directory where wasm module resides.
I have tested your code inside GaugeAircraft example from SDK. That example already loads fonts, images files from Data folder. And data folder have copied to package folder and have path to load (example for fonts) nvgCreateFont(nvgctx, "serif", "./data/Roboto-Regular.ttf");
File default.ln3 was placed inside add-on package directory C:\MSFS SDK\Samples\GaugeAircraft\Packages\mycompany-aircraft-wasm-gauge
View attachment 66359

Thanks lot,
guess you are damned right, i set the file inside SimObiects/Airplanes/myplane that's was not SDK intention..
i should have noted that sample aircraft could access to Data :-(
cheers
Mario