The close() function closes the file associated with the handle. The function returns 0 if successful, -1 to indicate an error.

int close (int fd);

Example :

#define EMBEDTRON "www.embedtron.com"

#define BUFFER_SIZE 20

int main() 

{

    char buffer[BUFFER_SIZE];

    int len = 0;

    int fh  = 1;

    if((fh=open("file.txt","w" )) == -1) 

    {

        printf("Create file failed");

        return -1;

    }

    if((len = write(fh,EMBEDTRON,strlen(EMBEDTRON))) != strlen(EMBEDTRON))

    {

        printf("Write data failed");

        return -2;

    }

    close(fh);

    return 0;

 }