Creates a temporary file. This function is deprecated because a more secure version is available; see tmpfile_s.

FILE *tmpfile( void );

If successful, tmpfile returns a stream pointer. Otherwise, it returns a NULL pointer.

The tmpfile function creates a temporary file and returns a pointer to that stream. The temporary file is created in the root directory. To create a temporary file in a directory other than the root, use tmpnam or tempnam in conjunction with fopen.

If the file cannot be opened, tmpfile returns a NULL pointer. This temporary file is automatically deleted when the file is closed, when the program terminates normally, or when _rmtmp is called, assuming that the current working directory does not change. The temporary file is opened in w+b (binary read/write) mode.

Failure can occur if you attempt more than TMP_MAX (see STDIO.H) calls with tmpfile.


Required header



For additional compatibility information, see Compatibility in the Introduction.


This example requires administrative privileges to run on Windows Vista.

// crt_tmpfile.c
// compile with: /W3
// This program uses tmpfile to create a
// temporary file, then deletes this file with _rmtmp.
#include <stdio.h>

int main( void )
   FILE *stream;
   char tempstring[] = "String to be written";
   int  i;

   // Create temporary files.
   for( i = 1; i <= 3; i++ )
      if( (stream = tmpfile()) == NULL ) // C4996
      // Note: tmpfile is deprecated; consider using tmpfile_s instead
         perror( "Could not open new temporary file\n" );
         printf( "Temporary file %d was created\n", i );

   // Remove temporary files.
   printf( "%d temporary files deleted\n", _rmtmp() );
Temporary file 1 was created
Temporary file 2 was created
Temporary file 3 was created
3 temporary files deleted

Not applicable. To call the standard C function, use PInvoke. For more information, see Platform Invoke Examples.

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