Page History

...

The file is opened for update with "wb+" mode, which means "truncate to zero length or create binary file for update." To the extent that the underlying system supports the concepts, the file is opened with exclusive (non-shared) access and has a file permission that prevents other users on the system from accessing the file.

It should be possible to open at least {{TMP_MAX_S}} temporary files during the lifetime of the program (this limit may be shared with {{tmpnam_s()}}).  The value of the macro {{TMP_MAX_S}} is only required to be 25

 \[[ISO/IEC TR 24731-1

The tmpfile_s() function is available on systems that support ISO/IEC TR 24731-1.

-2007|AA. C References#ISO/IEC TR 24731-1-2007]\].

TR 24731-1 notes the following regarding the use of {{

tmpfile_s()}} instead of {{tmpnam_s()}} \[[ISO/IEC TR 24731-1-2007|AA. C References#ISO/IEC TR 24731-1-2007]\]:

After a program obtains a file name using the tmpnam_s function and before the program creates a file with that name, the possibility exists that someone else may create a file with that same name. To avoid this race condition, the tmpfile_s function should be used instead of tmpnam_s when possible. One situation that requires the use of the tmpnam_s function is when the program needs to create a temporary directory rather than a temporary file.

...