cannot retarget getchar/read/getch

RE: cannot retarget getchar/read/getch

user3482 — Fri, 08 Mar 2019 19:55:18 GMT

I don't think it is libc issue but rather bad implementation in retarget.c. Proper retarget is like this:

base : github.com/.../stddev.c

uart retarget implementation : https://github.com/I-SYST/EHAL/blob/master/src/uart_retarget.c

use case example : github.com/.../uart_retarget_demo.cpp

RE: cannot retarget getchar/read/getch

user4098 — Fri, 08 Mar 2019 17:38:07 GMT

(man this "new" devzone is a terrible, terrible website. It's sacrificing actual usability for glitz and flashy UI!)

My code is not based off of anything, I just copied the retarget.c from an old project long, long ago and have been modifying and using it on several ARM systems, not just Nordic.

The .map file shows that getchar() is implemneted in libc.a (arm-none-eabi/lib/thumb/v7e-m/fpv4-sp/hard/libc.a) -- perhaps this has nothing to do with Nordic's SDK at all and everything to do with a bad implementation in libc which ships with gcc-arm-none-eabi-7-2018-q2-update.

RE: cannot retarget getchar/read/getch

user2116 — Thu, 07 Mar 2019 13:17:17 GMT

Hi Andrew

Is your project based on one of the existing SDK examples?

If yes, which one?

The map file should show which module implements the getchar() function, even if the source code does not. Could you have a look there, or share it with me?

Best regards
Torbjørn

RE: cannot retarget getchar/read/getch

user4098 — Wed, 06 Mar 2019 13:43:38 GMT

No IDE, just gcc and a Makefile.

im not sure I made the issue clear. getchar() is present in the binary. Something has implemented it, and it’s not calling any of the normal retargeted functions (__getchar, _read, _fgetc, etc.). The getchar implementation appears to be in one of the binary-only libraries in SDK15.0, as grepping the entire source tree reveals nothing useful.

Because of this, I can’t call getchar() I my high level code and have it actually pull data from my data source. stdio works (fgetc, etc) but I’m trying to understand the getchar issue.

RE: cannot retarget getchar/read/getch

user2116 — Wed, 06 Mar 2019 12:59:31 GMT

Hi Andrew

Which IDE/compiler are you using?

getchar() should be implemented in the retarget file, but I don't think any of our examples use it.

Best regards
Torbjørn