ftw: default flags to ftw-phys

More often than not, you want the FTW_PHYS flag when
calling the nftw function. Let's make that the default
in TXR's wrapper.

* ftw.c (ftw_wrap): Default to FTW_PHYS when flags
argument not given, rather than zero, subject to
compatibility option.
(ftw_init): Don't check for FTW_PHYS with ifdef, since
we relied on it being present. And anyway, any nftw
implementation must have that.

* txr.1: Documented.

2 files changed, 24 insertions, 4 deletions

diff --git a/ftw.c b/ftw.c
index 6984b7ff..43cfb9b9 100644
--- a/ftw.c
+++ b/ftw.c
@@ -43,6 +43,7 @@
 #include "signal.h"
 #include "unwind.h"
 #include "sysif.h"
+#include "txr.h"
 #include "ftw.h"
 
 #define max(a, b) ((a) > (b) ? (a) : (b))
@@ -111,7 +112,8 @@ val ftw_wrap(val dirpath, val fn, val flags_in, val nopenfd_in)
     return ret;
   } else {
     int nopenfd = c_num(default_arg(nopenfd_in, num_fast(20)), self);
-    int flags = c_num(default_arg(flags_in, zero), self);
+    val flags_dfl = if3(opt_compat && opt_compat <= 283, zero, num(FTW_PHYS));
+    int flags = c_num(default_arg(flags_in, flags_dfl), self);
     char *dirpath_u8 = utf8_dup_to(c_str(dirpath, self));
     int res = (s_callback = fn,
                nftw(dirpath_u8, ftw_callback, nopenfd, flags));
@@ -144,9 +146,7 @@ void ftw_init(void)
   prot1(&s_callback);
 
   /* ftw flags */
-#ifdef FTW_PHYS
   reg_varl(intern(lit("ftw-phys"), user_package), num_fast(FTW_PHYS));
-#endif
 #ifdef FTW_MOUNT
   reg_varl(intern(lit("ftw-mount"), user_package), num_fast(FTW_MOUNT));
 #endif
diff --git a/txr.1 b/txr.1
index 69b5e903..3f585b29 100644
--- a/txr.1
+++ b/txr.1
@@ -74306,9 +74306,22 @@ and
 arguments are reversed with respect to the C language interface.
 They are both optional;
 .meta flags
-defaults to zero, and
+defaults to the value of
+.code ftw-phys
+and
 .meta nopenfd
 defaults to 20.
+If an argument is given to
+.metn flags ,
+then the presence of the
+.code ftw-phys
+is no longer implied; the flag must be explicitly
+included in the argument in order to be present.
+
+Compatibility Note: the
+.meta flags
+parameter defaults to an argument value of zero in \*(TX
+versions 283 or lower.
 
 The
 .meta path-or-list
@@ -89972,6 +89985,13 @@ of these version values, the described behaviors are provided if
 is given an argument which is equal or lower. For instance
 .code "-C 103"
 selects the behaviors described below for version 105, but not those for 102.
+.IP 283
+In \*(TX 283 and older versions, the
+.meta flags
+parameter of the
+.code ftw
+function defaults to zero, rather than
+.codn ftw-phys .
 .IP 275
 In \*(TX 275 and older versions, the FFI type operator
 .code align