Clion writing static library encountered a strange problem, I also do not describe clearly, please answer

Today I was trying to write a static link library using Clion and found this problem:

This is the code for the header file:

#ifndef DB_HELLO_H
#define DB_HELLO_H

#include "stdio.h"

typedef struct{
    int a;
    int b;
}ts;

ts c = {
        .a = 6,
        .b = 10
};

void say(int a);

#endif

This is the code for the c file:

#include "hello.h"

void say(int num) {
    printf("%d\n", num);
}

After the

build, we get the.a static library

Create a new file and configure Cmake as follows:

< div class = "aw - list - img >

, write the following code in the c file:

#include "hello.h"

int main() {
    say(c.a);
}

To my surprise, it made an error, as follows:

FAILED: t1.exe
cmd.exe /C "cd . & & E: \ CLION2-1.1 \ bin \ mingw \ bin \ GCC exe - g CMakeFiles/t1. Dir/main c.o bj - o t1. Exe - Wl - out - implib libt1. DLL. A -Wl,--major-image-version,0,--minor-image-version,0 -LC:/Users/Administrator/CLionProjects/untitled -LG:/Cproject/lib -Wl,-Bstatic -ldb -Wl,-Bdynamic -lkernel32 -luser32 -lgdi32 -lwinspool -lshell32 -lole32 -loleaut32 -luuid -lcomdlg32 -ladvapi32 & & CD. "< br / > E: \ CLion 2022.3.1 \ bin \ mingw \ bin/ld exe: G:/Cproject/lib\libdb.a(hello.c.obj):C:/Users/Administrator/CLionProjects/db/hello.h:11: multiple definition of `c'; CMakeFiles/t1.dir/main.c.obj:G:/Cproject/include/hello.h:11: first defined here
collect2.exe: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.

Then I try another scheme, using printf:

#include "hello.h"

int main() {
    printf("%d", c.a);
}

No error is reported on this run, the correct number is printed

This is surprising to me. a member of structure c will get an error when used for say(), but not for printf(). It does the same thing, but the structure is defined inside the header file.

Here I am using clion's default configuration:

For answers, thanks