NAME
clearenv - clear the environment SYNOPSIS
#include
int clearenv(void); Feature Test Macro Requirements for glibc (see featuretestmacros(7)): clearenv(): SVIDSOURCE || BSDSOURCE 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 nonzero 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 adds only putenv(3), and rejected 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 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) COLOPHON
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Linux 2010-10-04 CLEARENV(3)