C <stdio.h> - rename() Function

The C <stdio.h> rename() function is used to change the name of a file. The file is identified by character string pointed to by oldname. The new filename is identified by character string pointed to by newname. If newname already exists, the behavior of this function is implementation-defined.

Syntax

int rename ( const char * oldname, const char * newname );

Parameters

Return Value

Returns 0 if the file is successfully renamed, otherwise non-zero value is returned.
On most library implementations, the errno variable is also set to a system-specific error code on failure.

Example:

Lets assume that we have a file called test.txt. The example below shows how to use rename() function is used to change the name of this file.

#include <stdio.h>
 
int main (){
  int result;
  char oldname[] = "test.txt";
  char newname[] = "test123.txt";

  //trying to rename the file
  result = rename(oldname, newname);

  //displaying the message
  if(result == 0)
    printf("File is successfully renamed.");
  else
    printf("Some error has occurred.");
  
  return 0;
}

If the file is renamed successfully, the following message will be shown:

File is successfully renamed.

Otherwise, the following message will be shown:

Some error has occurred.