# tmpnam

## PROLOG



           This manual page is part of the POSIX Programmer's Manual.  The
           Linux implementation of this interface may differ (consult the
           corresponding Linux manual page for details of Linux behavior), or
           the interface may not be implemented on Linux.
    


## NAME



           tmpnam — create a name for a temporary file
    


## SYNOPSIS



           #include <stdio.h>
    
           char *tmpnam(char *_s_);
    


## DESCRIPTION



           The functionality described on this reference page is aligned with
           the ISO C standard. Any conflict between the requirements
           described here and the ISO C standard is unintentional. This
           volume of POSIX.1‐2017 defers to the ISO C standard.
    
           The _tmpnam_() function shall generate a string that is a valid
           pathname that does not name an existing file. The function is
           potentially capable of generating {TMP_MAX} different strings, but
           any or all of them may already be in use by existing files and
           thus not be suitable return values.
    
           The _tmpnam_() function generates a different string each time it is
           called from the same process, up to {TMP_MAX} times. If it is
           called more than {TMP_MAX} times, the behavior is implementation-
           defined.
    
           The implementation shall behave as if no function defined in this
           volume of POSIX.1‐2017, except _tempnam_(), calls _tmpnam_().
    
           The _tmpnam_() function need not be thread-safe if called with a
           NULL parameter.
    


## RETURN VALUE



           Upon successful completion, _tmpnam_() shall return a pointer to a
           string. If no suitable string can be generated, the _tmpnam_()
           function shall return a null pointer.
    
           If the argument _s_ is a null pointer, _tmpnam_() shall leave its
           result in an internal static object and return a pointer to that
           object. Subsequent calls to _tmpnam_() may modify the same object.
           If the argument _s_ is not a null pointer, it is presumed to point
           to an array of at least L_tmpnam **char** s; _tmpnam_() shall write its
           result in that array and shall return the argument as its value.
    


## ERRORS



           No errors are defined.
    
           _The following sections are informative._
    


## EXAMPLES



       **Generating a Pathname**
           The following example generates a unique pathname and stores it in
           the array pointed to by _ptr_.
    
               #include <stdio.h>
               ...
               char pathname[L_tmpnam+1];
               char *ptr;
    
               ptr = tmpnam(pathname);
    


## APPLICATION USAGE



           This function only creates pathnames. It is the application's
           responsibility to create and remove the files.
    
           Between the time a pathname is created and the file is opened, it
           is possible for some other process to create a file with the same
           name.  Applications may find _tmpfile_() more useful.
    
           Applications should use the _tmpfile_(), _mkstemp_(), or _mkdtemp_()
           functions instead of the obsolescent _tmpnam_() function.
    


## RATIONALE



           None.
    


## FUTURE DIRECTIONS



           The _tmpnam_() function may be removed in a future version.
    


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