Bugfix #4363

In windows, without temp path set, the 'save buffers' render option crashes.

I've coded a blenlib BLI_is_writable(char *filename) to check for such
cases. This is not much needed in Blender, since the open() command is
checked for. However, file saving happens deep inside the C++ exr lib, and
it throws an exception crash when a file cannot be written.

2 files changed, 16 insertions, 1 deletions

diff --git a/source/blender/blenlib/BLI_blenlib.h b/source/blender/blenlib/BLI_blenlib.h
index c920d7127ae..28fca2c29a6 100644
--- a/source/blender/blenlib/BLI_blenlib.h
+++ b/source/blender/blenlib/BLI_blenlib.h
@@ -256,7 +256,7 @@ int    BLI_exist(char *name);
 void  BLI_recurdir_fileops(char *dirname);
 int BLI_link(char *file, char *to);
 int BLI_backup(char *file, char *from, char *to);
-
+int BLI_is_writable(char *filename);
 
 /**
  * @attention Do not confuse with BLI_exist
diff --git a/source/blender/blenlib/intern/fileops.c b/source/blender/blenlib/intern/fileops.c
index 9a4ffca4844..232546b89ca 100644
--- a/source/blender/blenlib/intern/fileops.c
+++ b/source/blender/blenlib/intern/fileops.c
@@ -125,6 +125,21 @@ int BLI_gzip(char *from, char *to) {
 	return 0;
 }
 
+/* return 1 when file can be written */
+int BLI_is_writable(char *filename)
+{
+	int file;
+	
+	file = open(filename, O_BINARY | O_RDWR | O_CREAT | O_TRUNC, 0666);
+	
+	if (file < 0)
+		return 0;
+	else {
+		close(file);
+		return 1;
+	}
+}
+
 #ifdef WIN32
 
 static char str[MAXPATHLEN+12];