VALID_REVNUM are defined in svn_types_impl.h */

/** Valid revision numbers begin at 0 */
#define SVN_IS_VALID_REVNUM(n) ((n) >= 0)

/** Not really invalid...just unimportant -- one day, this can be its
 * own unique value, for now, just make it the same as
 * #SVN_INVALID_REVNUM.
 */
#define SVN_IGNORED_REVNUM ((svn_revnum_t) -1)

/** Convert NULL-terminated C string @a str to a revision number. */
#define SVN_STR_TO_REV(str) ((svn_revnum_t) atol(str))

/**
 * Parse NULL-terminated C string @a str as a revision number and
 * store its value in @a rev.  If @a endptr is non-NULL, then the
 * address of the first non-numeric character in @a str is stored in
 * it.  If there are no digits in @a str, then @a endptr is set (if
 * non-NULL), and the error #SVN_ERR_REVNUM_PARSE_FAILURE error is
 * returned.  Negative numbers parsed from @a str are considered
 * invalid, and result in the same error.
 *
 * @since New in 1.5.
 */
svn_error_t *
svn_revnum_parse(svn_revnum_t *rev,
                 const char *str,
                 const char **endptr);

/** Originally intended to be used in printf()-style functions to format
 * revision numbers.  Deprecated due to incompatibilities with language
 * translation tools (e.g. gettext).
 *
 * New code should use a bare "%ld" format specifier for formatting revision
 * numbers.
 *
 * @deprecated Provided for backward compatibility with the 1.0 API.
 */
#define SVN_REVNUM_T_FMT "ld"