NAME
clearenv - clear the environment
SYNOPSIS
#include <stdlib.h>
I int clearenv(void);
DESCRIPTION
The
R clearenv ()
function clears the environment of all name-value
pairs and sets the value of the external variable
environ
to NULL.
RETURN VALUE
The
R clearenv ()
function returns zero on success, and a non-zero
value on failure.
VERSIONS
Not in libc4, libc5.
In glibc since glibc 2.0.
CONFORMING TO
Various Unix variants (DG/UX, HP-UX, QNX, ...).
POSIX.9 (bindings for FORTRAN77).
POSIX.1-1996 did not accept
R clearenv ()
and
putenv(3),
but changed its mind and scheduled these functions for some
later issue of this standard (cf. B.4.6.1).
However, POSIX.1-2001
only adds
putenv(3),
and rejected
R clearenv ().
NOTES
Used in security-conscious applications.
If it is unavailable
the assignment
environ = NULL;
will probably do.
The DG/UX and Tru64 man pages write: If
environ
has been modified by anything other than the
putenv(3),
getenv(3),
or
R clearenv ()
functions, then
R clearenv ()
will return an error and the process environment will remain unchanged.
SEE ALSO
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