| getenv.3 (169146) | getenv.3 (169177) |
|---|---|
| 1.\" Copyright (c) 1988, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the American National Standards Committee X3, on Information 6.\" Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without --- 16 unchanged lines hidden (view full) --- 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)getenv.3 8.2 (Berkeley) 12/11/93 | 1.\" Copyright (c) 1988, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the American National Standards Committee X3, on Information 6.\" Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without --- 16 unchanged lines hidden (view full) --- 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)getenv.3 8.2 (Berkeley) 12/11/93 |
| 33.\" $FreeBSD: head/lib/libc/stdlib/getenv.3 169146 2007-04-30 19:37:10Z ache $ | 33.\" $FreeBSD: head/lib/libc/stdlib/getenv.3 169177 2007-05-01 16:02:44Z ache $ |
| 34.\" | 34.\" |
| 35.Dd April 30, 2007 | 35.Dd October 12, 2006 |
| 36.Dt GETENV 3 37.Os 38.Sh NAME 39.Nm getenv , 40.Nm putenv , 41.Nm setenv , 42.Nm unsetenv 43.Nd environment variable functions 44.Sh LIBRARY 45.Lb libc 46.Sh SYNOPSIS 47.In stdlib.h 48.Ft char * 49.Fn getenv "const char *name" 50.Ft int 51.Fn setenv "const char *name" "const char *value" "int overwrite" 52.Ft int | 36.Dt GETENV 3 37.Os 38.Sh NAME 39.Nm getenv , 40.Nm putenv , 41.Nm setenv , 42.Nm unsetenv 43.Nd environment variable functions 44.Sh LIBRARY 45.Lb libc 46.Sh SYNOPSIS 47.In stdlib.h 48.Ft char * 49.Fn getenv "const char *name" 50.Ft int 51.Fn setenv "const char *name" "const char *value" "int overwrite" 52.Ft int |
| 53.Fn putenv "char *string" 54.Ft int | 53.Fn putenv "const char *string" 54.Ft void |
| 55.Fn unsetenv "const char *name" 56.Sh DESCRIPTION 57These functions set, unset and fetch environment variables from the 58host 59.Em environment list . | 55.Fn unsetenv "const char *name" 56.Sh DESCRIPTION 57These functions set, unset and fetch environment variables from the 58host 59.Em environment list . |
| 60For compatibility with differing environment conventions, 61the given arguments 62.Fa name 63and 64.Fa value 65may be appended and prepended, 66respectively, 67with an equal sign 68.Dq Li \&= . |
|
| 60.Pp 61The 62.Fn getenv 63function obtains the current value of the environment variable, 64.Fa name . 65The application should not modify the string pointed 66to by the 67.Fn getenv --- 15 unchanged lines hidden (view full) --- 83.Fa overwrite 84is zero, the 85variable is not reset, otherwise it is reset 86to the given 87.Fa value . 88.Pp 89The 90.Fn putenv | 69.Pp 70The 71.Fn getenv 72function obtains the current value of the environment variable, 73.Fa name . 74The application should not modify the string pointed 75to by the 76.Fn getenv --- 15 unchanged lines hidden (view full) --- 92.Fa overwrite 93is zero, the 94variable is not reset, otherwise it is reset 95to the given 96.Fa value . 97.Pp 98The 99.Fn putenv |
| 91function takes an argument of the form ``name=value'' and 92puts it directly into the current environment, 93so altering the argument shall change the environment. 94If the variable 95.Fa name 96does not exist in the list, 97it is inserted with the given 98.Fa value . 99If the variable 100.Fa name 101does exist, it is reset to the given 102.Fa value . | 100function takes an argument of the form ``name=value'' and is 101equivalent to: 102.Bd -literal -offset indent 103setenv(name, value, 1); 104.Ed |
| 103.Pp 104The 105.Fn unsetenv 106function 107deletes all instances of the variable name pointed to by 108.Fa name 109from the list. 110.Sh RETURN VALUES 111The 112.Fn getenv 113function returns the value of the environment variable as a 114.Dv NUL Ns 115-terminated string. 116If the variable 117.Fa name 118is not in the current environment, 119.Dv NULL 120is returned. 121.Pp | 105.Pp 106The 107.Fn unsetenv 108function 109deletes all instances of the variable name pointed to by 110.Fa name 111from the list. 112.Sh RETURN VALUES 113The 114.Fn getenv 115function returns the value of the environment variable as a 116.Dv NUL Ns 117-terminated string. 118If the variable 119.Fa name 120is not in the current environment, 121.Dv NULL 122is returned. 123.Pp |
| 122.Rv -std setenv putenv unsetenv | 124.Rv -std setenv putenv |
| 123.Sh ERRORS 124.Bl -tag -width Er | 125.Sh ERRORS 126.Bl -tag -width Er |
| 125.It Bq Er EINVAL 126The function 127.Fn setenv 128or 129.Fn unsetenv 130failed because the 131.Fa name 132is a 133.Dv NULL 134pointer, points to an empty string, or points to a string containing an 135.Dq Li \&= 136character. | |
| 137.It Bq Er ENOMEM 138The function 139.Fn setenv 140or 141.Fn putenv 142failed because they were unable to allocate memory for the environment. 143.El 144.Sh SEE ALSO 145.Xr csh 1 , 146.Xr sh 1 , 147.Xr execve 2 , 148.Xr environ 7 149.Sh STANDARDS 150The 151.Fn getenv 152function conforms to 153.St -isoC . | 127.It Bq Er ENOMEM 128The function 129.Fn setenv 130or 131.Fn putenv 132failed because they were unable to allocate memory for the environment. 133.El 134.Sh SEE ALSO 135.Xr csh 1 , 136.Xr sh 1 , 137.Xr execve 2 , 138.Xr environ 7 139.Sh STANDARDS 140The 141.Fn getenv 142function conforms to 143.St -isoC . |
| 154The 155.Fn setenv , 156.Fn putenv 157and 158.Fn unsetenv 159functions conforms to 160.St -p1003.1-2001 . | |
| 161.Sh HISTORY 162The functions 163.Fn setenv 164and 165.Fn unsetenv 166appeared in 167.At v7 . 168The --- 22 unchanged lines hidden --- | 144.Sh HISTORY 145The functions 146.Fn setenv 147and 148.Fn unsetenv 149appeared in 150.At v7 . 151The --- 22 unchanged lines hidden --- |