Standard C Library Functions                           tmpnam(3C)

NAME
     tmpnam, tmpnam_r, tempnam - create a name  for  a  temporary
     file

SYNOPSIS
     #include <stdio.h>

     char *tmpnam(char *s);

     char *tmpnam_r(char *s);

     char *tempnam(const char *dir, const char *pfx);

DESCRIPTION
     These functions generate file names that can safely be  used
     for a temporary file.

  tmpnam()
     The tmpnam() function always generates a file name using the
     path  prefix defined as P_tmpdir in the <stdio.h> header. On
     Solaris  systems,  the  default  value   for   P_tmpdir   is
     /var/tmp.  If  s  is  NULL, tmpnam() leaves its result in an
     internal static area and returns a pointer to that area. The
     next call to tmpnam() will destroy the contents of the area.
     If s is not NULL, it is assumed to  be  the  address  of  an
     array  of  at least L_tmpnam bytes, where L_tmpnam is a con-
     stant defined in <stdio.h>;  tmpnam() places its  result  in
     that array and returns s.

  tmpnam_r()
     The  tmpnam_r()  function  has  the  same  functionality  as
     tmpnam()  except  that  if s is a null pointer, the function
     returns NULL. This interface is as proposed in the  POSIX.4a
     Draft  #6 document, and is subject to change to be compliant
     to the standard when it is accepted.

  tempnam()
     The tempnam() function allows the user to control the choice
     of  a  directory. The argument dir points to the name of the
     directory in which the file is to be created. If dir is NULL
     or  points to a string that is not a name for an appropriate
     directory, the  path  prefix  defined  as  P_tmpdir  in  the
     <stdio.h>  header is used. If that directory is not accessi-
     ble, /tmp is used. If, however, the TMPDIR environment vari-
     able  is set in the user's environment, its value is used as
     the temporary-file directory.

     Many applications prefer that temporary files  have  certain
     initial character sequences in their names. The pfx argument
     may be NULL or point to a string of up to five characters to
     be  used  as  the  initial  characters of the temporary-file
     name.

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Standard C Library Functions                           tmpnam(3C)

     The tempnam() function uses malloc(3C) to allocate space for
     the  constructed  file  name,  and returns a pointer to this
     area. Any pointer value returned from tempnam() may serve as
     an  argument to free(3C) (see malloc(3C)). If tempnam() can-
     not return the expected result for any reason (for  example,
     malloc(3C)  failed),  or  if  none  of  the  above-mentioned
     attempts to find an appropriate directory was successful,  a
     null  pointer  is  returned. This function fails if there is
     not enough space.

USAGE
     These functions generate a different  file  name  each  time
     they are called.

     Files created using these functions and either fopen(3C)  or
     creat(2) are temporary only in the sense that they reside in
     a directory intended for temporary use, and their names  are
     unique.  It  is the user's responsibility to remove the file
     when its use is ended.

     If called more than TMP_MAX (defined in <stdio.h>) times  in
     a single process, these functions start recycling previously
     used names.

     Between the time a file name is  created  and  the  file  is
     opened,  it  is  possible for some other process to create a
     file with the same name. This can never happen if that other
     process  is using these functions or mktemp(3C) and the file
     names are  chosen  to  render  duplication  by  other  means
     unlikely.

ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | MT-Level                    | See NOTES below.            |
    |_____________________________|_____________________________|

SEE ALSO
     creat(2),  unlink(2),   fopen(3C),   free(3C),   malloc(3C),
     mktemp(3C), tmpfile(3C), attributes(5)

NOTES
     The tmpnam() function is unsafe  in  multithreaded  applica-
     tions.   The  tempnam()  function  is  safe in multithreaded
     applications and should be used instead.

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Standard C Library Functions                           tmpnam(3C)

     When compiling multithreaded applications,  the   _REENTRANT
     flag  must be defined on the compile line.  This flag should
     be used only with multithreaded applications.

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