intro.1, _exit.2, access.2, alarm.2, alloc_hugepages.2, arch_prctl.2, bind.2, chdir...

[thirdparty/man-pages.git] / man3 / clearenv.3

diff --git a/man3/clearenv.3 b/man3/clearenv.3
index d96b047595424f1b4ff79c6f881428becf842f24..7e4d86dd0c372c3a684d7b988e17fd635a00eb67 100644 (file)
--- a/man3/clearenv.3
+++ b/man3/clearenv.3
@@ -1,5 +1,6 @@
 .\" Copyright 2001 John Levon <moz@compsoc.man.ac.uk>
 .\"
+.\" %%%LICENSE_START(VERBATIM)
 .\" Permission is granted to make and distribute verbatim copies of this
 .\" manual provided the copyright notice and this permission notice are
 .\" preserved on all copies.
@@ -8,7 +9,7 @@
 .\" manual under the conditions for verbatim copying, provided that the
 .\" entire resulting derived work is distributed under the terms of a
 .\" permission notice identical to this one.
-.\" 
+.\"
 .\" Since the Linux kernel and libraries are constantly changing, this
 .\" manual page may be incorrect or out-of-date.  The author(s) assume no
 .\" responsibility for errors or omissions, or for damages resulting from
@@ -16,59 +17,76 @@
 .\" have taken the same level of care in the production of this manual,
 .\" which is licensed free of charge, as they might when working
 .\" professionally.
-.\" 
+.\"
 .\" Formatted or processed versions of this manual, if unaccompanied by
 .\" the source, must acknowledge the copyright and authors of this work.
+.\" %%%LICENSE_END
 .\"
 .\" Additions, aeb, 2001-10-17.
-.TH CLEARENV 3  2001-10-17 "Linux Programmer's Manual"
+.TH CLEARENV 3  2010-10-04 "Linux" "Linux Programmer's Manual"
 .SH NAME
 clearenv \- clear the environment
 .SH SYNOPSIS
 .nf
 .B #include <stdlib.h>
 .sp
-.BI "int clearenv(void);"
+.B "int clearenv(void);"
 .fi
+.sp
+.in -4n
+Feature Test Macro Requirements for glibc (see
+.BR feature_test_macros (7)):
+.in
+.sp
+.BR clearenv ():
+_SVID_SOURCE || _BSD_SOURCE
 .SH DESCRIPTION
-The \fBclearenv\fP() function clears the environment of all name-value
+The
+.BR clearenv ()
+function clears the environment of all name-value
 pairs and sets the value of the external variable
 .I environ
 to NULL.
-
-.SH "RETURN VALUE"
-The \fBclearenv\fP() function returns zero on success, and a non-zero
+.SH RETURN VALUE
+The
+.BR clearenv ()
+function returns zero on success, and a nonzero
 value on failure.
-.\" Most versions of Unix return -1 on error, or do not even have errors.
-.\" Glibc info and the Watcom C library document "a non-zero value".
-
-.SH AVAILABILITY
-Not in libc4, libc5. In glibc since glibc 2.0.
-
-.SH "CONFORMING TO"
-Various Unix variants (DG/UX, HP-UX, QNX, ...).
+.\" Most versions of UNIX return -1 on error, or do not even have errors.
+.\" Glibc info and the Watcom C library document "a nonzero value".
+.SH VERSIONS
+Not in libc4, libc5.
+In glibc since glibc 2.0.
+.SH CONFORMING TO
+Various UNIX variants (DG/UX, HP-UX, QNX, ...).
 POSIX.9 (bindings for FORTRAN77).
-POSIX.1-1996 did not accept \fBclearenv\fP() and \fIputenv\fP(),
+POSIX.1-1996 did not accept
+.BR clearenv ()
+and
+.BR putenv (3),
 but changed its mind and scheduled these functions for some
-later issue of this standard (cf. B.4.6.1). 
+later issue of this standard (cf. B.4.6.1).
 However, POSIX.1-2001
-only adds \fIputenv\fP(), and rejected \fBclearenv\fP().
-
+only adds
+.BR putenv (3),
+and rejected
+.BR clearenv ().
 .SH NOTES
-Used in security-conscious applications. If it is unavailable
+Used in security-conscious applications.
+If it is unavailable
 the assignment
-.RS
 .nf
-       environ = NULL;
+
+    environ = NULL;
+
 .fi
-.RE
 will probably do.
 .LP
-The DG/UX and Tru64 manpages write: If
+The DG/UX and Tru64 man pages write: If
 .I environ
 has been modified by anything other than the
-.BR putenv (),
-.BR getenv (),
+.BR putenv (3),
+.BR getenv (3),
 or
 .BR clearenv ()
 functions, then
@@ -76,7 +94,7 @@ functions, then
 will return an error and the process environment will remain unchanged.
 .\" .LP
 .\" HP-UX has a ENOMEM error return.
-.SH "SEE ALSO"
+.SH SEE ALSO
 .BR getenv (3),
 .BR putenv (3),
 .BR setenv (3),