/opt/IBM/openxlC/17.1.1/bin/ibm-clang -pthread  -Wall -Wextra -Werror=implicit-function-declaration unistd/pipe2.c -o unistd/pipe2 -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE -lm -lpthread -lrt -latomic
unistd/pipe2.c:11:7: error: call to undeclared function 'pipe2'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration]
        if ( pipe2(fds, O_CLOEXEC) < 0 )
             ^
unistd/pipe2.c:11:7: note: did you mean 'pipe'?
/usr/include/unistd.h:202:21: note: 'pipe' declared here
extern int _NOTHROW(pipe, (int []));
                    ^
/usr/include/comp_macros.h:51:26: note: expanded from macro '_NOTHROW'
#define _NOTHROW(_F, _B) _F _B
                         ^
1 error generated.