Using below function in one of the .h file. if i am using function deceleration without inline getting multiple definitions error and now after adding inline getting above warning so help me to suppress the warning i mean how to fix the warning.
inline void (*log_fcn)(int level, std::string format, unsigned int line_no, std::string file_name, ...);
CodePudding user response：
Using below function in one of the .h file.
It is not a function. It is a variable of function pointer type.
how to fix the warning
Option 1: Use C 17 or later language version.
Option 2: Don't use C 17 features like inline variables. To use a non-inline namespace scope variable, you can declare it extern in the header, and define it in one translation unit.
CodePudding user response：
inline variables are a C 17 feature. But since you're using C 11 you can make use of extern as shown below:
header.h
#ifndef MYHEADER_H
#define MYHEADER_H
#include <string>
//THIS IS A DECLARATION. Note the use of extern keyword here.
extern void (*log_fcn)(int level, std::string format, unsigned int line_no, std::string file_name, ...);
#endif
source.cpp
#include "header.h"
void func(int level, std::string format, unsigned int line_no, std::string file_name, ...)
{
}
//this is definition
void (*log_fcn)(int level, std::string format,
unsigned int line_no, std::string file_name, ...) = func;
//------------------------------------------------------------------^^^^--->initializer
main.cpp
#include "header.h"
int main()
{
}