flang/test/Driver/pthread.f90

   1 ! In release 2.34, glibc removed libpthread as a separate library. All the
   2 ! pthread_* functions were subsumed into libc, so linking that is sufficient.
   3 ! However, when linking against older glibc builds, the explicit link of
   4 ! -pthread will be required. More details are here:
   5 !
   6 ! https://developers.redhat.com/articles/2021/12/17/why-glibc-234-removed-libpthread#the_developer_view
   7 !
   8 ! This makes it difficult to write a test that requires the -pthread flag in
   9 ! order to pass. Checking for the presence of -lpthread in the linker flags is
  10 ! not reliable since the linker could just skip the flag altogether if it is
  11 ! linking against a new libc implementation.
  12
  13 ! RUN: %flang -### -pthread /dev/null -o /dev/null 2>&1 | FileCheck %s
  14 ! RUN: %flang -### -Xflang -pthread /dev/null -o /dev/null 2>&1 | FileCheck %s
  15
  16 ! How the -pthread flag is handled is very platform-specific. A lot of that
  17 ! functionality is tested by clang, and the flag itself is handled by clang's
  18 ! driver that flang also uses. Instead of duplicating all that testing here,
  19 ! just check that the presence of the flag does not raise an error. If we need
  20 ! more customized handling of -pthread, the tests for that can be added here.
  21 !
  22 ! CHECK-NOT: error: