Hi woboyle,
Thank you very much for your reply.
On Ubuntu linux, sigqueue with thread id does not work.
My intention was to have 4 slave threads send the same signal to the master thread asyncronously so accessing the master's associtive structure by the slaves must be carried out with a mutex.
So for lack of simpler solutions, I will have 4 slaves send 4 different signals because only information I need to send with the signal is from which slave the signal is originating.
Hiromichi

Dear Linux experts,
Is it possible to send a signal to a pthread with sigqueue() ?
The argument of the function is a process ID and not a thread ID.
I can use pthread_kill() but I need to send an accompanying value as in sigqueue().
Thanks,
Hiromichi