[FFmpeg-devel] [PATCH] Fix return value check for open()

[Måns Rullgård]

Martin Storsj? <martin at martin.st> writes:

> Hi,
>
> According to all manuals I've checked (both linux & darwin manpages, and 
> msdn docs), open() returns exactly -1 on error, not any generic negative 
> number. The attached patch fixes the return value check in 
> libavformat/file.c.
>
> On WinCE, the return values from successful open() calls are negative 
> sometimes, making url_open() calls fail randomly. This is fixed by the 
> attached patch.
>
> diff --git a/libavformat/file.c b/libavformat/file.c
> index da0ce15..d2cb530 100644
> --- a/libavformat/file.c
> +++ b/libavformat/file.c
> @@ -51,7 +51,7 @@ static int file_open(URLContext *h, const char *filename, int flags)
>      access |= O_BINARY;
>  #endif
>      fd = open(filename, access, 0666);
> -    if (fd < 0)
> +    if (fd == -1)
>          return AVERROR(ENOENT);
>      h->priv_data = (void *) (intptr_t) fd;
>      return 0;

Patch looks OK.  That said, this is what SUSv3 says on open:

  Upon successful completion, the function shall open the file and
  return a non-negative integer [...].  Otherwise, -1 shall be
  returned [...].

So yes, checking for -1 is correct.  However, I consider other
negative return values an OS bug.

-- 
M?ns Rullg?rd
mans at mansr.com