char *mktemp( char *template ); 

用于：Create a unique filename.

Windows中，函数叫下面两个名字，包含于 io.h 文件中

char *_mktemp( char *template );

wchar_t *_wmktemp( wchar_t *template );

Return Value

Each of these functions returns a pointer to the modified template. The function returns NULL if template is badly formed or no more unique names can be created from the given template.

template的格式：baseXXXXXX，base为任意字符，然后是六个X。（记住，是六个哦）

Example

/* MKTEMP.C: The program uses _mktemp to create
 * five unique filenames. It opens each filename
 * to ensure that the next name is unique.
 */

#include"stdio.h" 
#include "io.h"
#include "string.h"

char *template = "fnXXXXXX";
char *result;
char names[5][9];

void main( void )
{
   int i;
   FILE *fp;

   for( i = 0; i < 5; i++ )
   {
      strcpy( names[i], template );
      /* Attempt to find a unique filename: */
      result = _mktemp( names[i] );
      if( result == NULL )
         printf( "Problem creating the template" );
      else
      {
         if( (fp = fopen( result, "w" )) != NULL )
            printf( "Unique filename is %s\n", result );
         else
            printf( "Cannot open %s\n", result );
         fclose( fp );
      }
   }
}

Output

Unique filename is fna00141
Unique filename is fnb00141
Unique filename is fnc00141
Unique filename is fnd00141
Unique filename is fne00141