ensure-dir: return nil when exists.

* sysif.c (mkdir_nothrow_exists): Return nil in the existence
case, when the object is a directory or a symlink to one.

* txr.1: Updated.

2 files changed, 12 insertions, 6 deletions

diff --git a/sysif.c b/sysif.c
index 369f1890..a12d625f 100644
--- a/sysif.c
+++ b/sysif.c
@@ -339,6 +339,7 @@ static val mkdir_nothrow_exists(val path, val mode)
       ret = num(errno);
       break;
     case EEXIST:
+      ret = nil;
 #if HAVE_SYS_STAT
       {
         struct stat st;
@@ -384,7 +385,7 @@ static val ensure_dir(val path, val mode)
                           partial_path, sep, pop(&split_path), nao);
   }
 
-  if (ret != t) {
+  if (integerp(ret)) {
     int eno = c_num(ret);
     uw_throwf(errno_to_file_error(eno),
               lit("ensure-dir: ~a: ~d/~s"), path, ret,
diff --git a/txr.1 b/txr.1
index ebee463c..bcbc1520 100644
--- a/txr.1
+++ b/txr.1
@@ -57494,13 +57494,18 @@ are subject to the system
 
 The function
 .code ensure-dir
-is similar to
-.code mkdir
-except that it attempts to create all the missing parent directories
-as necessary, and does not throw an error if
+also creates a directory named
+.metn path .
+Unlike
+.codn mkdir ,
+it also attempt to create all the necessary parent directories,
+and does not throw an error if
 .meta path
 refers to an existing object, if that object is a directory or a symbolic
-link to a directory.
+link to a directory. Rather, in that case it returns
+.code nil
+instead of
+.codn t .
 
 .coNP Function @ chdir
 .synb