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Annotation of 43BSDReno/lib/libc/stdlib/getenv.3, revision 1.1

1.1     ! root        1: .\" Copyright (c) 1988 The Regents of the University of California.
        !             2: .\" All rights reserved.
        !             3: .\"
        !             4: .\" Redistribution and use in source and binary forms are permitted
        !             5: .\" provided that: (1) source distributions retain this entire copyright
        !             6: .\" notice and comment, and (2) distributions including binaries display
        !             7: .\" the following acknowledgement:  ``This product includes software
        !             8: .\" developed by the University of California, Berkeley and its contributors''
        !             9: .\" in the documentation or other materials provided with the distribution
        !            10: .\" and in all advertising materials mentioning features or use of this
        !            11: .\" software. Neither the name of the University nor the names of its
        !            12: .\" contributors may be used to endorse or promote products derived
        !            13: .\" from this software without specific prior written permission.
        !            14: .\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
        !            15: .\" IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
        !            16: .\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        !            17: .\"
        !            18: .\"    @(#)getenv.3    6.9 (Berkeley) 5/17/90
        !            19: .\"
        !            20: .TH GETENV 3 "May 17, 1990"
        !            21: .AT 3
        !            22: .SH NAME
        !            23: getenv, putenv, setenv, unsetenv \- manipulate environmental variables
        !            24: .SH SYNOPSIS
        !            25: .nf
        !            26: .ft B
        !            27: #include <stdlib.h>
        !            28: 
        !            29: char *
        !            30: getenv(const char *name);
        !            31: 
        !            32: setenv(const char *name, const char *value, int overwrite);
        !            33: 
        !            34: putenv(const char *string);
        !            35: 
        !            36: void
        !            37: unsetenv(const char *name);
        !            38: .ft R
        !            39: .fi
        !            40: .SH DESCRIPTION
        !            41: .I Getenv
        !            42: searches the environment list (see
        !            43: .IR environ (7))
        !            44: for a string of the form \fIname\fP\fB=\fP\fIvalue\fP and returns
        !            45: a pointer to the string
        !            46: .I value
        !            47: if such a string is present, and a NULL pointer if it is not.
        !            48: .PP
        !            49: .I Setenv
        !            50: searches the environment list as
        !            51: .I getenv
        !            52: does; if the string
        !            53: .I name
        !            54: is not found, a string of the form \fIname\fP\fB=\fP\fIvalue\fP is
        !            55: added to the environment.
        !            56: If it is found, and
        !            57: .I overwrite
        !            58: is non-zero, its value is changed to
        !            59: .IR value .
        !            60: .I Setenv
        !            61: returns 0 on success and -1 on failure, setting the external variable
        !            62: .IR errno .
        !            63: .PP
        !            64: .I Putenv
        !            65: takes an argument of the form ``\fIname\fR=\fIvalue\fR'' and is the
        !            66: equivalent of:
        !            67: .sp
        !            68: .RS
        !            69: setenv(name, value, 1);
        !            70: .RE
        !            71: .PP
        !            72: .I Unsetenv
        !            73: removes all occurrences of the string
        !            74: .I name
        !            75: from the environment.
        !            76: There is no library provision for completely removing the current
        !            77: environment.
        !            78: It is suggested that the following code be used to do so.
        !            79: .sp
        !            80: .RS
        !            81: .nf
        !            82: static char    *envinit[1];
        !            83: extern char    **environ;
        !            84: environ = envinit;
        !            85: .fi
        !            86: .RE
        !            87: .PP
        !            88: All of these routines permit, but do not require, a trailing equals
        !            89: (``='') sign on
        !            90: .I name
        !            91: or a leading equals sign on
        !            92: .IR value .
        !            93: .SH ERRORS
        !            94: .TP
        !            95: [ENOMEM]
        !            96: .I Setenv
        !            97: or
        !            98: .I putenv
        !            99: failed because they were unable to allocate memory for the environment.
        !           100: .SH SEE ALSO
        !           101: csh(1), sh(1), execve(2), environ(7)
        !           102: .SH STANDARDS
        !           103: .B Getenv
        !           104: conforms to ANSI X3.159-1989 (``ANSI C'').

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