Ngx_write_chain_to_temp_file and NGX_AGAIN

Server NGINX
1

Hi.

I’m reading the code for writing a temporary buffer in a temporary file,
and I have noted something not very clear.

Here is the code (core/ngx_file.c):
ngx_write_chain_to_temp_file(ngx_temp_file_t *tf, ngx_chain_t *chain)
{
ngx_int_t rc;

 if (tf->file.fd == NGX_INVALID_FILE) {
     rc = ngx_create_temp_file(&tf->file, tf->path, tf->pool,
                               tf->persistent, tf->clean,
                               tf->access);

     if (rc == NGX_ERROR || rc == NGX_AGAIN) {
         return rc;
     }

However it seems that ngx_create_temp_file never returns NGX_AGAIN.

Moreover the functions ngx_event_pipe_write_chain_to_temp_file
(event/ngx_event_pipe.c) and ngx_http_write_request_body
(http/ngx_http_request_body) only check for NGX_ERROR and not for
NGX_AGAIN.

So, should I check for NGX_ERROR only?

Thanks Manlio P.

2

On Tue, Nov 27, 2007 at 07:08:31PM +0100, Manlio P. wrote:

                              tf->persistent, tf->clean,

Moreover the functions ngx_event_pipe_write_chain_to_temp_file
(event/ngx_event_pipe.c) and ngx_http_write_request_body
(http/ngx_http_request_body) only check for NGX_ERROR and not for NGX_AGAIN.

So, should I check for NGX_ERROR only?

Yes. This is artefact of times when I plan to do aync open() files using
special threads.