Fingerprint Scanner Library Issue

Other Miscellaneous
1

I am a teacher, and I’m having trouble with compiling code for the fingerprint scanners on the Sparkfun Redboards. I have not had these issues in the past. The sensor is wired correctly, but I keep getting the following error: lib/Fingerprint_FPS_GT511C3/Fingerprint_FPS_GT511C3.cpp:209:1: no return statement in function returning non-void [-Werror=return-type]

I tried a second sensor and also tried it on a different redboard and the same issue comes up. From looking at the library, I’m not sure what exactly would need to change in my code. Any help you can give me on that?

2

Here is my code:

https://docs.google.com/document/d/1UYb … sp=sharing

3

your issue is in Fingerprint_FPS_GT511C3.cpp. That is not part of the code you shared. A subroutine should return a value, but is apparently not . Do you have a link from where you downloaded the Fingerprint_FPS_GT511C3.?

4

Here are links to my code:

Main Code - https://docs.google.com/document/d/1UYb … sp=sharing

Fingerprint_PFS_GT511C3.cpp Library - https://docs.google.com/document/d/1FVj … sp=sharing

Fingerprint_PFS_GT511C3.h Library - https://docs.google.com/document/d/1K3e … sp=sharing

5

paulvha:
your issue is in Fingerprint_FPS_GT511C3.cpp. That is not part of the code you shared. A subroutine should return a value, but is apparently not . Do you have a link from where you downloaded the Fingerprint_FPS_GT511C3.?

Here are the 2 code libraries I am using:

.cpp - https://docs.google.com/document/d/1FVj … sp=sharing

.h - https://docs.google.com/document/d/1K3e … sp=sharing

6

Can not get complete allignment with the download but I think in around line 209 in Fingerprint_FPS_GT511C3.cpp, routine CheckParsing() add " return(retval);" at the end. Like this :

// checks to see if the byte is the proper value, and logs it to the serial channel if not
bool Response_Packet::CheckParsing(byte b, byte propervalue, byte alternatevalue, char* varname, bool UseSerialDebug)
{
        bool retval = (b != propervalue) && (b != alternatevalue);
        if ((UseSerialDebug) && (retval))
        {
                Serial.print("Response_Packet parsing error ");
                Serial.print(varname);
                Serial.print(" ");
                Serial.print(propervalue, HEX);
                Serial.print(" || ");
                Serial.print(alternatevalue, HEX);
                Serial.print(" != ");
                Serial.println(b, HEX);
        }
        return(retval);

}

I wonder where the library is coming from as I miss on a number of subroutines the typeof data that is returned (e.g. int, uint16_t)

7

The coding for the Redboard is done on Particle.io, and I don’t have the option to edit library code. I’m not sure what to do next. Thanks for looking at that!