How to compile the g++ object file with gcc

Here is an example shows how to compiler a program with gcc with objects files which are compiled by g++

Example codes:
( Reference from here )

test.c　
　#include
　#include
　#include "adio.h"
　#include "adstring.h"
　int main()
　{
　　char input[21];
　　char buffer[11];
　　char buf[11];
　　const char* str = "hello world!!";
　　adstring_strcpy(buffer, str, 11);
　　puts(buffer);
　　adio_fgets(input, 21, stdin);
　　puts(input);
　　adstring_strcpy(buffer, input, 5);
　　puts(buffer);
　　int a = 12345;
　　puts(adstring_itoa(buf, a, 11));
　　puts(buf);
　　return 0;
　}

adio.h
　#ifndef ADVENCE_IO_H
　#define ADVENCE_IO_H
　#include
　char* adio_fgets(char* buf, int num, FILE* fp);
　void adio_stdinclean(void);
　#endif

adstring.h
　#ifndef ADVENCE_STRING_H
　#define ADVENCE_STRING_H
　char* adstring_strcpy(char* to, const char* from, int num);
　char* adstring_itoa(char* to, int from, int num);
　#endif

adio.c
　#include
　#include
　char* adio_gets(char* buf, int num, FILE* fp)
　{
　　char* find = 0;
　　fgets(buf, num, stdin);
　　if ((find = strrchr(buf, '\n')))
　　{
　　　*find = '\0′;
　　}
　　else
　　{
　　　while (fgetc(fp) != '\n');
　　}
　　return buf;
　}
　void adio_stdinclean()
　{
　　while (getchar() != '\n');
　}

adstring.c
　#include
　#include
　char* adstring_strcpy(char* to, const char* from, int num)
　{
　　int size = num-1;
　　strncpy(to, from, size);
　　if (strlen(from) >= size)
　　{
　　　to[size] = '\0′;
　　}
　　return to;
　}
　char* adstring_itoa(char* to, int from, int num)
　{
　　char tmp[11];
　　sprintf(tmp, "%d", from);
　　adstring_strcpy(to, tmp, num);
　　return to;
　}



Make static library , here we assume object files need to be compiler in g++
　g++ adio.c adstring.c -Wall -c (this line will come out with adio.o adstring.o)
　ar rcs libadlib.a adio.o adstring.o (archieve into libadlib.a file)

　gcc test.c -I. -L. -ladlib -o test

Here, there are some errors say that the function with object files is not found.
The reason is that compiler will change c++'s function name while compiling.
In order to tell compiler not to change function name, we can use extern "C"

We can modify adio.c adstring.c into :

adio.c
　#include
　#include

　#ifdef __cplusplus
　extern "C" {
　#endif

　char* adio_gets(char* buf, int num, FILE* fp)
　{
　　char* find = 0;
　　fgets(buf, num, stdin);
　　if ((find = strrchr(buf, '\n')))
　　{
　　　*find = '\0′;
　　 }
　　else
　　{
　　　while (fgetc(fp) != '\n');
　　}
　　return buf;
　}
　void adio_stdinclean()
　 {
　　while (getchar() != '\n');
　}

　#ifdef __cplusplus
　}
　#endif

adstring.c
　#include
　#include

　#ifdef __cplusplus
　extern "C" {
　#endif

　char* adstring_strcpy(char* to, const char* from, int num)
　{
　　int size = num-1;
　　strncpy(to, from, size);
　　if (strlen(from) >= size)
　　{
　　　to[size] = '\0′;
　　} 　　return to;
　}
　char* adstring_itoa(char* to, int from, int num)
　{
　　char tmp[11];
　　sprintf(tmp, "%d", from);
　　adstring_strcpy(to, tmp, num);
　　return to;
　}


　#ifdef __cplusplus
　}
　#endif