confstr(3)                                                   confstr(3)

  confstr()

  NAME

    confstr() - get string-valued configurable variables

  SYNOPSIS

    #include 

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

  DESCRIPTION

    The confstr(3) 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 include file .
    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.

    When the macros _ALL_SOURCE(1) or _XOPEN_SOURCE(1) are defined, or if
    _POSIX_C_SOURCE(1)==2, then these are also available:

    _CS_SHELL
        The POSIX shell.

    _CS_INSTALLEDDIR
        The directory in which INTERIX is installed.

    _CS_TMPDIR
        The INTERIX temporary directory.

    _CS_ETCDIR

    _CS_BINDIR

    _CS_INCLUDEDIR

    _CS_LIBDIR

    _CS_USRDIR

    _CS_PUBSDIR

  RETURN VALUES

    If the call to confstr(3) is not successful, -1 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(3) function may fail and set error for any of the errors
    specified for the library function malloc(3).

    In addition, the following errors may be reported:

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

  USAGE NOTES

    The confstr function is thread safe.

    The confstr function is not async-signal safe.