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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 n unistd.h .Ft size_t .Fn confstr "int name" "char *buf" "size_t len" .Sh DESCRIPTION f -symbolic This interface is obsoleted by .Xr sysctl 3 . .Ef
p The .Fn confstr function provides a method for applications to get configuration defined string values.
p The .Fa name argument specifies the system variable to be queried. Symbolic constants for each name value are found in the n 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.
p The available values are as follows:
p l -tag -width "123456" t 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 .
p In addition, the following errors may be reported: l -tag -width Er t 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 x 4.4 . .Sh BUGS The standards require us to return 0 both on errors, and when the value is not set.