When compiling with C++, it treats void (*rte_delay_us)(unsigned int us); as definition of the global variable. So further linking with librte_eal fails.
Fixes: b4d63fb62240 ("eal: customize delay function") Steps to reproduce: $ cat rttm1.cpp #include <iostream> #include <rte_eal.h> #include <rte_cycles.h> using namespace std; int main(int argc, char *argv[]) { int ret = rte_eal_init(argc, argv); rte_delay_us(1); cout << "return code "; cout << ret; return ret; } $ g++ -m64 -I/${RTE_SDK}/${RTE_TARGET}/include -c -o rttm1.o rttm1.cpp $ gcc -m64 -pthread -o rttm1 rttm1.o -ldl -Wl,-lstdc++ \ -L/${RTE_SDK}/${RTE_TARGET}/lib -Wl,-lrte_eal .../librte_eal.a(eal_common_timer.o): (.bss+0x0): multiple definition of `rte_delay_us' rttm1.o:(.bss+0x0): first defined here collect2: error: ld returned 1 exit status $ nm rttm1.o | grep rte_delay_us 0000000000000092 t _GLOBAL__sub_I_rte_delay_us 0000000000000000 B rte_delay_us Signed-off-by: Konstantin Ananyev <konstantin.ananyev at intel.com> --- lib/librte_eal/common/include/generic/rte_cycles.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/librte_eal/common/include/generic/rte_cycles.h b/lib/librte_eal/common/include/generic/rte_cycles.h index 96a2da9..00103ca 100644 --- a/lib/librte_eal/common/include/generic/rte_cycles.h +++ b/lib/librte_eal/common/include/generic/rte_cycles.h @@ -188,7 +188,7 @@ rte_get_timer_hz(void) * @param us * The number of microseconds to wait. */ -void +extern void (*rte_delay_us)(unsigned int us); /** -- 2.4.3