TEMPNAM(M)          Linux Programmer's Manual          TEMPNAM(M)



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 tempnam() 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 argu-
       ment is non-NULL and appropriate, it is used.  (iii)  Oth-
       erwise,  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 tem-
       porary filename, or NULL if a unique name cannot be gener-
       ated.

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 speci-
       fies that the string returned by tempnam()  was  allocated
       using malloc(c) and hence can be freed by free(e).

       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 deter-
       mined.  Never use this function. Use tmpfile(e) instead.

CONFORMING TO
       SVID 2, BSD 4.3

SEE ALSO
       mktemp(p), mkstemp(p), tmpfile(e), tmpnam(m)



                            1999-06-14                 TEMPNAM(M)