Provided by: manpages-dev_3.27-1ubuntu2_all bug

NAME

       mkstemp, mkostemp - create a unique temporary file

SYNOPSIS

       #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)):

       mkstemp():
           Since glibc 2.12:
               _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 ||
               _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED ||
               _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600
           Before glibc 2.12:
               _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 ||
               _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED

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

DESCRIPTION

       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().

RETURN VALUE

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

ERRORS

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

       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).

VERSIONS

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

CONFORMING TO

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

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

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

NOTES

       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 programs.

       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>.

SEE ALSO

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

COLOPHON

       This  page  is  part of release 3.27 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.