Constructs a unique filename.

    Format

      #include  <stdlib.h>

      int mkstemp  (char *template);

1 - Argument

 template

    A pointer to a string that is replaced with a unique filename.
    The string in the template argument must be a filename with six
    trailing Xs.

2 - Description

    The mkstemp function replaces the six trailing Xs of the string
    pointed to by template with a unique set of characters, and
    returns a file descriptor for the file open for reading and
    writing.

    The string pointed to by template should look like a filename
    with six trailing X's. The mkstemp function replaces each X with
    a character from the portable file-name character set, making
    sure not to duplicate an existing filename.

    If the string pointed to by template does not contain six
    trailing Xs, -1 is returned.

3 - Return Values

    x                  An open file descriptor.
    -1                 Indicates an error. (The string pointed to by
                       template does not contain six trailing Xs.)