Updated: 2021/Apr/14

CONFSTR(3)                 Library Functions Manual                 CONFSTR(3)

     confstr - get string-valued configurable variables

     Standard C Library (libc, -lc)

     #include <unistd.h>

     confstr(int name, char *buf, size_t len);

     This interface is obsoleted by sysctl(3).

     The confstr() function provides a method for applications to get
     configuration defined string values.

     The name argument specifies the system variable to be queried.  Symbolic
     constants for each name value are found in the <unistd.h> header.  The
     len argument specifies the size of the buffer referenced by the argument
     buf.  If len is non-zero, buf is a non-null pointer, and name has a
     value, up to len - 1 bytes of the value are copied into the buffer buf.
     The copied value is always null terminated.

     The available values are as follows:

             Return a value for the PATH environment variable that finds all
             the standard utilities.

     If the call to confstr is not successful, 0 is returned and errno is set
     appropriately.  Otherwise, if the variable does not have a configuration
     defined value, 0 is returned and 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 len, the string in
     buf was truncated.

     The confstr function may fail and set error for any of the errors
     specified for the library functions malloc(3) and sysctl(3).

     In addition, the following errors may be reported:

     [EINVAL]           The value of the name argument is invalid.


     The confstr function conforms to IEEE Std 1003.2-1992 ("POSIX.2").

     The confstr function first appeared in 4.4BSD.

     The standards require us to return 0 both on errors, and when the value
     is not set.

NetBSD 9.99                     April 22, 2010                     NetBSD 9.99