Hi,
(Read the update at the bottom first)
Readme.md for the xdot library cites the version below.
“# libmDot-dev
Bleeding edge development version of the mDot library. This version of the library is not guaranteed to be stable or well tested and should not be used in production or deployment scenarios.
This library is compaible with mbed-os version 5.1.3 and above.”
————————–
According to this posting, the MBED online compiler (which I am using) automatically uses the latest version of mbed-os
https://os.mbed.com/questions/78849/How-can-you-find-out-the-revision-of-mbe/
When I click on mbed-os in the MBED online environment, it cites:
Last Modified: 13 Jan 2020
Revision: 5345:c966348
status: synced
———————————
I’d rather not publish the project to a public forum, however the code recently added looks something like this:
——————————————
#include <iostream>
#include <sstream>
#include <iomanip>
#include <list>
#include “mbed.h”
#include <string>
#include <cstdio>
#include <cstdint>
#include <math.h> // modf
using namespace std;
// GpsReading class, which represents data of a GPS fix and
// member functions to manipulate the data
class GpsReading {
public:
std::string hexLatitudeString;
std::string hexLongitudeString;
//
// other irrelevant stuff here removed from the example…
//
const uint8_t deviceType = 0x00; // 0x00 is default
// note the default setting of deviceType
// should be moved into a constructor..
std::ostringstream loraPayloadString;
// use ostringstream to construct the output string
// ref https://stackoverflow.com/questions/29320434/convert-array-of-uint8-t-to-string-in-c
// constructors and member functions
// member function to convert a GPS reading data set into bytes ready to send to
// the Lora transmitter
std::string translateToSendBytes ();
private:
};
string GpsReading::translateToSendBytes ( ) {
//
// other irrelevant stuff here removed from the example…
//
// using ostringstream class to construct the string
// reference
// https://stackoverflow.com/questions/29320434/convert-array-of-uint8-t-to-string-in-c
string GpsReading::translateToSendBytes ( ) {
//
// other irrelevant stuff here removed from the example…
//
loraPayloadString << std::uppercase << std::hex << (int)deviceType;
printf(“payloadString = %s”, loraPayloadString.str());
return loraPayloadString.str();
}
—————————-
A couple of footnotes:
1. I believe I had made some other changes before I got pulled off the task and had to come back to it again after a while. It was compiling at an earlier revision of the design, but in the online environment who knows what can change, the compiler, the mbed-os library version all can change behind the scenes. So the ostringstream latest change could possibly be a red herring. But at the moment I am inclined to believe that it has to do with ostringstream.
2. I have not test compiled the code fragment above which I hacked together from the code. Apologies for any bugs, hopefully illustrative at least.
3. I just retested without changing anything. It seemed to recompile mbed-os but threw the same error. The error help points to the link below:
https://os.mbed.com/cookbook/Compiler-Error-L6218E
////////// UPDATE /////////////////
4. OK….after writing the above, I ran an “update” on mbed-os as it was not updated since Jan 2020, and now it comes up with a different compile-time complaint:
Error: Cannot pass non-trivial object of type ‘std::__1::basic_ostringstream<char, std::__1::char_traits<char>, std::__1::allocator<char> >::string_type’ (aka ‘basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >’) to variadic function; expected type from format string was ‘char *’ [-Wnon-pod-varargs] in “examples/src/read_gnss_data.cpp”, Line: 352, Col: 38
Line 352 was this line:
printf(“payloadString = %s”, loraPayloadString.str());
If I comment that line out, I hit a different bug which I am still investigating. So will share the details above for your info but I need to work on this a bit more to investigate if there is still an issue. It looks like the mbed-os library update seemed to make a difference at least.
It is also obvious that mbed-os version needs to be updated manually, it is not automatic at all. The help here was a little ambiguous:
https://os.mbed.com/questions/78849/How-can-you-find-out-the-revision-of-mbe/
“Yes, I believe that the online compiler uses the “latest” branch by default…”
Thanks.
