CONFSTR(3)             FreeBSD Library Functions Manual             CONFSTR(3)

NAME
     confstr - get string-valued configurable variables

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <unistd.h>

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

DESCRIPTION
     This interface is specified by IEEE Std 1003.1-2001 ("POSIX.1").  A more
     flexible (but non-portable) interface is provided by sysctl(3).

     The confstr() function provides a method for applications to get
     configuration defined string values.  Shell programmers needing access to
     these parameters should use the getconf(1) utility.

     The name argument specifies the system variable to be queried.  Symbolic
     constants for each name value are found in the include file <unistd.h>.
     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:

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

RETURN VALUES
     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.

ERRORS
     The confstr() function may fail and set errno 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.

SEE ALSO
     getconf(1), pathconf(2), sysconf(3), sysctl(3)

HISTORY
     The confstr() function first appeared in 4.4BSD.

FreeBSD 13.1-RELEASE-p6        December 3, 2006        FreeBSD 13.1-RELEASE-p6