Name
clearenv — clear the environment
DESCRIPTION
The clearenv() function
clears the environment of all name-value pairs and sets the
value of the external variable environ to NULL.
RETURN VALUE
The 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
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
clearenv().
NOTES
Used in security-conscious applications. If it is
unavailable the assignment
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 clearenv() functions, then clearenv() will return an error and the
process environment will remain unchanged.
SEE ALSO
getenv(3), putenv(3), setenv(3), unsetenv(3), environ(7)
Copyright 2001 John Levon <moz@compsoc.man.ac.uk>
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Additions, aeb, 2001-10-17.
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