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.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
.\"
.\" 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.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" 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.\" manual page may be incorrect or out-of-date.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
.\" the use of the information contained herein. The author(s) may not
.\" 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.
.\"
.\" References consulted:
.\" Linux libc source code
.\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
.\" 386BSD man pages
.\" Modified Sat Jul 24 18:20:58 1993 by Rik Faith (faith@cs.unc.edu)
.\" Modified Fri Feb 14 21:47:50 1997 by Andries Brouwer (aeb@cwi.nl)
.TH SETENV 3 "April 4, 1993" "BSD" "Linux Programmer's Manual"
.SH NAME
setenv \- change or add an environment variable
.SH SYNOPSIS
.nf
.B #include <stdlib.h>
.sp
.BI "int setenv(const char *" name ", const char *" value ", int " overwrite );
.sp
.BI "void unsetenv(const char *" name );
.fi
.SH DESCRIPTION
The \fBsetenv()\fP function adds the variable \fIname\fP to the
environment with the value \fIvalue\fP, if \fIname\fP does not
already exist. If \fIname\fP does exist in the environment, then
its value is changed to \fIvalue\fP if \fIoverwrite\fP is non-zero;
if \fIoverwrite\fP is zero, then the value of \fIname\fP is not
changed.
.PP
The \fBunsetenv()\fP function deletes the variable \fIname\fP from
the environment.
.SH "RETURN VALUE"
The \fBsetenv()\fP function returns zero on success, or \-1 if there
was insufficient space in the environment.
.SH "CONFORMING TO"
BSD 4.3
.SH "SEE ALSO"
.BR getenv (3),
.BR putenv (3),
.BR environ (5)
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