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       mkstemp, mkostemp - create a unique temporary file


       #include <stdlib.h>

       int mkstemp(char *template);

       int mkostemp(char *template, int flags);

       int mkstemps(char *template, int suffixlen);

       int mkostemps(char *template, int suffixlen, int flags);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 ||
           || /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200112L

       mkostemp(): _GNU_SOURCE
       mkstemps(): _BSD_SOURCE || _SVID_SOURCE
       mkostemps(): _GNU_SOURCE


       The mkstemp() function generates a unique temporary filename from  template,  creates  and
       opens the file, and returns an open file descriptor for the file.

       The  last six characters of template must be "XXXXXX" and these are replaced with a string
       that makes the filename unique.  Since it will be modified, template must not be a  string
       constant, but should be declared as a character array.

       The  file  is created with permissions 0600, that is, read plus write for owner only.  (In
       glibc versions 2.06 and earlier, the file is created with permissions 0666, that is,  read
       and  write  for  all  users.)   The  returned file descriptor provides both read and write
       access to the file.  The file is opened with the open(2) O_EXCL  flag,  guaranteeing  that
       the caller is the process that creates the file.

       The  mkostemp()  function is like mkstemp(), with the difference that flags as for open(2)
       may be specified in flags (e.g., O_APPEND, O_SYNC).

       The mkstemps() function is like mkstemp(), except that the string in template  contains  a
       suffix of suffixlen characters.  Thus, template is of the form prefixXXXXXXsuffix, and the
       string XXXXXX is modified as for mkstemp().

       The mkostemps() function is to mkstemps() as mkostemp() is to mkstemp().


       On success, these functions return the file descriptor of the temporary file.   On  error,
       -1 is returned, and errno is set appropriately.


       EEXIST Could  not  create  a  unique temporary filename.  Now the contents of template are

       EINVAL For mkstemp() and mkostemp(): The last six characters of template were not  XXXXXX;
              now template is unchanged.

              For  mkstemps()  and  mkostemps(): template is less than (6 + suffixlen) characters
              long, or the last 6 characters before the suffix in template were not XXXXXX.

       These functions may also fail with any of the errors described for open(2).


       mkostemp() is available since glibc 2.7.  mkstemps() and mkostemps() are  available  since
       glibc 2.11.


       mkstemp(): 4.3BSD, POSIX.1-2001.

       mkstemps(): unstandardized, but appears on several other systems.

       mkostemp() and mkostemps(): are glibc extensions.


       The  old  behavior  of  creating  a file with mode 0666 may be a security risk, especially
       since other UNIX flavors use 0600, and somebody might overlook this  detail  when  porting

       More  generally,  the  POSIX  specification  of mkstemp() does not say anything about file
       modes, so the application should make sure its file mode creation mask (see  umask(2))  is
       set appropriately before calling mkstemp() (and mkostemp()).

       The  prototype  for  mktemp()  is  in  <unistd.h> for libc4, libc5, glibc1; glibc2 follows
       POSIX.1 and has the prototype in <stdlib.h>.


       mkdtemp(3), mktemp(3), tempnam(3), tmpfile(3), tmpnam(3)


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