.\" 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this one .\" .\" Since the Linux kernel and libraries are constantly changing, this .\" manual page may be incorrect or out-of-date.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 Thu Apr 8 15:00:12 1993, David Metcalfe .\" Modified Sat Jul 24 18:44:45 1993, Rik Faith (faith@cs.unc.edu) .TH PUTENV 3 "April 8, 1993" "GNU" "Linux Programmer's Manual" .SH NAME putenv \- change or add an environment variable .SH SYNOPSIS .nf .B #include .sp .BI "int putenv(const char *" string ); .fi .SH DESCRIPTION The \fBputenv()\fP function adds or changes the value of environment variables. The argument \fIstring\fP is of the form \fIname = value\fP. If \fIname\fP does not already exist in the environment, then \fIstring\fP is added to the environment. If \fIname\fP does exist, then the value of \fIname\fP in the environment is changed to \fIvalue\fP. .SH "RETURN VALUE" The \fBputenv()\fP function returns zero on success, or \-1 if an error occurs. .SH ERRORS .TP .B ENOMEM Insufficient space to allocate new environment. .SH "CONFORMING TO" SVID 3, POSIX, BSD 4.3 .SH "SEE ALSO" .BR getenv "(3), " setenv "(3), " unsetenv (3)