rename

int rename(const char *old_filename, const char *new_filename);

Changes name of file oldname to newname. Returns non-zero on failure.

/* 
 * rename example code
 * http://code-reference.com/c/stdio.h/rename 
 */
 
#include <stdio.h> /* including standard library */
//#include <windows.h> /* uncomment this for Windows */
 
#define FILENAME "test_tmp.txt"
 
int main ( void )
{
FILE *tmpfile;
char string[20];
tmpfile = fopen(FILENAME, "w");
 
if (tmpfile == 0 ) {
perror("cannot open file");
}
 
 fprintf (tmpfile, "temporary file for c remove example\n");
 fclose(tmpfile);
 
 rename (FILENAME,"test_new.txt");
 
 return 0; 
}

  ./rename
  
  file will be created
  write text into file "temporary file for c rename example"

  file will be renamed into test_new.txt