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\" @(#)confstr.3 8.1 (Berkeley) 6/4/93
\"
Dd April 22, 2010
Dt CONFSTR 3
Os
Sh NAME
Nm confstr
Nd get string-valued configurable variables
Sh LIBRARY
Lb libc
Sh SYNOPSIS
In unistd.h
Ft size_t
Fn confstr "int name" "char *buf" "size_t len"
Sh DESCRIPTION
Bf -symbolic
This interface is obsoleted by
Xr sysctl 3 .
Ef
Pp
The
Fn confstr
function provides a method for applications to get configuration
defined string values.
Pp
The
Fa name
argument specifies the system variable to be queried.
Symbolic constants for each name value are found in the
In unistd.h
header.
The
Fa len
argument specifies the size of the buffer referenced by the
argument
Fa buf .
If
Fa len
is non-zero,
Fa buf
is a non-null pointer, and
Fa name
has a value, up to
Fa len
\- 1 bytes of the value are copied into the buffer
Fa buf .
The copied value is always null terminated.
Pp
The available values are as follows:
Pp
Bl -tag -width "123456"
It Li _CS_PATH
Return a value for the
Ev PATH
environment variable that finds all the standard utilities.
El
Sh RETURN VALUES
If the call to
Nm confstr
is not successful, 0 is returned and
Va errno
is set appropriately.
Otherwise, if the variable does not have a configuration defined value,
0 is returned and
Va errno
is not modified.
Otherwise, the buffer size needed to hold the entire configuration-defined
value is returned.
If this size is greater than the argument
Fa len ,
the string in
Fa buf
was truncated.
Sh ERRORS
The
Nm confstr
function may fail and set
Va error
for any of the errors specified for the library functions
Xr malloc 3
and
Xr sysctl 3 .
Pp
In addition, the following errors may be reported:
Bl -tag -width Er
It Bq Er EINVAL
The value of the
Fa name
argument is invalid.
El
Sh SEE ALSO
Xr sysctl 3
Sh STANDARDS
The
Nm confstr
function conforms to
St -p1003.2-92 .
Sh HISTORY
The
Nm confstr
function first appeared in
Bx 4.4 .
Sh BUGS
The standards require us to return 0 both on errors, and when the value
is not set.
