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