CODEWITHSUNDEEP
c
longleggedlemon
longleggedlemon

Reputation: 13

global variable from main.c is undeclared in header file function

the main.c contains a global variable called cell2VoltageUV which is given a value by function: updateMeasurements(); this function is also located inside the main.c but not in the main function.

whenever I try to print the cell2VoltageUV using a function in another .c file which also has a .h header file, I get the error:

'cell2VoltageUV' undeclared (first use in this function)

if i just do printf(cell2VoltageUV); in the main function i get the correct value but if the same printf(cell2VoltageUV); is located in another .c file function i get the error.

how do I get the correct value inside of the function I'm making?

ps. this is my first post here and I'm relatively new to c programming (Arduino experience only), this project I'm working on already has a lot of functions built-in and I'm trying to add more features.

Upvotes: 0

Views: 634

Answers (1)

0___________
0___________

Reputation: 67979

lets say that your variable is of type int;

int cell2VoltageU;

Then in any other file you use this variable you must have 

extern int cell2VoltageU;

Upvotes: 1

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