fclose

#include <stdio.h>
#include <stdlib.h>
 
int main(void)
{
 const char* fname = "/tmp/unique_name.txt"; // or tmpnam(NULL);
 int is_ok = EXIT_FAILURE ;
 
 FILE * fp = fopen (fname, "w+");
 if (!fp)
 {
 perror ("File opening failed");
 return is_ok;
 }
 fputs ("Hello, world!\n", fp);
 rewind (fp);
 
 int c; // note: int, not char, required to handle EOF
 while ((c = fgetc (fp)) != EOF ) // standard C I/O file reading loop
 putchar (c);
 
 if (ferror (fp))
 puts ("I/O error when reading");
 else if (feof (fp))
 {
 puts ("End of file is reached successfully");
 is_ok = EXIT_SUCCESS ;
 }
 
 fclose(fp);
 remove (fname);
 return is_ok;
}

Hello, world!
End of file is reached successfully