Race condition in multithread.c example

[korepanovnd-Sochi]

Specify which documentation you found a problem with

Example multithread.c

The problem

Example multithread.c has a race condition. Pointer to integer 'i' variable is passed to thread function.
Immediately after threads creation, variable 'i' assigned a new value. As result, from 2 to 3 threads get equal 'i' values, and getting same urls

[icing]

Any chance you'd like to propose a PR that improves the example?

[korepanovnd-Sochi]

Yes, I have patch for multithread.c example, and new version of multithread.c file

multithread.c
multithread.c.race.patch

[icing]

Thanks! Made that into #19526, @bagder will add you as a curl contributor when merging this.