tempnam

TEMPNAM(3)		  Linux Programmer’s Manual		   TEMPNAM(3)



NAME
       tempnam - create a name for a temporary file

SYNOPSIS
       #include <stdio.h>

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

DESCRIPTION
       The  tempnam()  function returns a pointer to a string that is a valid
       filename, and such that a file with this name did not exist when temp-
       nam()  checked.	 The  filename	suffix of the pathname generated will
       start with pfx in case pfx is a non-NULL string of at most five bytes.
       The  directory prefix part of the pathname generated is required to be
       ‘appropriate’ (often that at least  implies  writable).	 Attempts  to
       find  an	 appropriate directory go through the following steps: (i) In
       case the environment variable TMPDIR exists and contains the  name  of
       an  appropriate	directory,  that is used.  (ii) Otherwise, if the dir
       argument is non-NULL and appropriate, it is  used.   (iii)  Otherwise,
       P_tmpdir	 (as  defined  in  <stdio.h>) is used when appropriate.	 (iv)
       Finally an implementation-defined directory may be used.

RETURN VALUE
       The tempnam() function returns a pointer to a unique  temporary	file-
       name, or NULL if a unique name cannot be generated.

ERRORS
       ENOMEM Allocation of storage failed.


NOTES
       SUSv2  does not mention the use of TMPDIR; glibc will use it only when
       the program is not suid.	 SVID2	specifies  that	 the  directory	 used
       under (iv) is /tmp.  SVID2 specifies that the string returned by temp-
       nam() was allocated using malloc(3) and hence can be freed by free(3).

       The  tempnam()  function	 generates a different string each time it is
       called, up to TMP_MAX (defined in <stdio.h>) times. If  it  is  called
       more than TMP_MAX times, the behaviour is implementation defined.

       In  case	 the pfx argument has length larger than five, glibc will use
       the first five bytes.  Upon failure to find a unique name, glibc	 will
       return EEXIST.

BUGS
       The  precise  meaning of ‘appropriate’ is undefined; it is unspecified
       how accessibility of a directory is determined.	Never use this	func-
       tion. Use mkstemp(3) instead.

CONFORMING TO
       SVID 2, BSD 4.3, POSIX 1003.1-2003

SEE ALSO
       mktemp(3), mkstemp(3), tmpfile(3), tmpnam(3)



				  1999-06-14			   TEMPNAM(3)