The include file <thread.h>, used with the -lthread library, compiles code that is upward compatible with earlier releases of the Solaris Operating Environment. This library contains both interfaces—those with Solaris semantics and those with POSIX semantics. To call thr_setconcurrency(3THR) with POSIX threads, your program needs to include <thread.h>.
The include file <pthread.h>, used with the
-lpthread library, compiles code that is conformant with
the multithreading interfaces defined by the POSIX 1003.1c standard. For complete
POSIX compliance, the define flag _POSIX_C_SOURCE should
be set to a (
long) value ≥ 199506:
cc [flags] file... -D_POSIX_C_SOURCE=N (where N 199506L)
You can mix Solaris threads and POSIX threads in the same application, by including both <thread.h> and <pthread.h>, and linking with either the -lthread or -lpthread library.
In mixed use, Solaris semantics prevail when compiling with -D_REENTRANT and linking with -lthread, whereas POSIX semantics prevail when compiling with -D_POSIX_C_SOURCE and linking with -lpthread.