uniform ngx_directio_on/off() interface with other file functions
diff --git a/src/core/ngx_open_file_cache.c b/src/core/ngx_open_file_cache.c
index aa87fd2..5f6e0b2 100644
--- a/src/core/ngx_open_file_cache.c
+++ b/src/core/ngx_open_file_cache.c
@@ -525,7 +525,7 @@
         of->fd = fd;
 
         if (of->directio <= ngx_file_size(&fi)) {
-            if (ngx_directio_on(fd) == -1) {
+            if (ngx_directio_on(fd) == NGX_FILE_ERROR) {
                 ngx_log_error(NGX_LOG_ALERT, log, ngx_errno,
                               ngx_directio_on_n " \"%s\" failed", name);
 
diff --git a/src/core/ngx_output_chain.c b/src/core/ngx_output_chain.c
index 590da4f..3ff25ff 100644
--- a/src/core/ngx_output_chain.c
+++ b/src/core/ngx_output_chain.c
@@ -514,7 +514,7 @@
 #if (NGX_HAVE_ALIGNED_DIRECTIO)
 
         if (ctx->unaligned) {
-            if (ngx_directio_off(src->file->fd) == -1) {
+            if (ngx_directio_off(src->file->fd) == NGX_FILE_ERROR) {
                 ngx_log_error(NGX_LOG_ALERT, ctx->pool->log, ngx_errno,
                               ngx_directio_off_n " \"%s\" failed",
                               src->file->name.data);
@@ -550,7 +550,7 @@
 
             err = ngx_errno;
 
-            if (ngx_directio_on(src->file->fd) == -1) {
+            if (ngx_directio_on(src->file->fd) == NGX_FILE_ERROR) {
                 ngx_log_error(NGX_LOG_ALERT, ctx->pool->log, ngx_errno,
                               ngx_directio_on_n " \"%s\" failed",
                               src->file->name.data);