[Ffmpeg-devel] Stream file handle hijacking by another thread

Stas Oskin stas.oskin
Sun Feb 18 14:34:18 CET 2007

> Apparently, the h->priv_data somehow resets to 0x0, which in turn sets
> the file descriptor to 0 as well. This leads to the mentioned errors,
> and apparently to the bug of several threads writing to same file.

I traced the issue to the begining, and have found the cause for the
problem. Some of the file descriptors (fd) are set to 0 from the
start, from the open() function:

static int file_open(URLContext *h, const char *filename, int flags)
    fd = open(filename, access, 0666); /* fd gets 0 */
    h->priv_data = (void *)(size_t)fd; /* priv_data gets 0 as well */

This happens for several threads in the same process. AFAIK open()
should gurantee unique fd, but this is not the case here.

Can anyone advice what should be done here?

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