diff --git a/driver/others/blas_server_omp.c b/driver/others/blas_server_omp.c
index f7008fb088..2135310577 100644
--- a/driver/others/blas_server_omp.c
+++ b/driver/others/blas_server_omp.c
@@ -126,7 +126,7 @@ void openblas_set_num_threads(int num_threads) {
 int blas_thread_init(void){
 
 #if defined(__FreeBSD__) && defined(__clang__)
-extern int openblas_omp_num_threads_env();
+extern int openblas_omp_num_threads_env(void);
 
    if(blas_omp_number_max <= 0)
 	   blas_omp_number_max= openblas_omp_num_threads_env();
diff --git a/driver/others/dynamic_zarch.c b/driver/others/dynamic_zarch.c
index 5b45aae2f5..dd26c8e80c 100644
--- a/driver/others/dynamic_zarch.c
+++ b/driver/others/dynamic_zarch.c
@@ -13,7 +13,7 @@ extern gotoblas_t gotoblas_Z14;
 
 #define NUM_CORETYPES 4
 
-extern int openblas_verbose();
+extern int openblas_verbose(void);
 extern void openblas_warning(int verbose, const char* msg);
 
 char* gotoblas_corename(void) {
diff --git a/driver/others/memory_qalloc.c b/driver/others/memory_qalloc.c
index 6174d9b75e..a2593e01f7 100644
--- a/driver/others/memory_qalloc.c
+++ b/driver/others/memory_qalloc.c
@@ -288,7 +288,7 @@ int  goto_get_num_procs  (void) {
   return blas_cpu_number;
 }
 
-void openblas_fork_handler()
+void openblas_fork_handler(void)
 {
   // This handler shuts down the OpenBLAS-managed PTHREAD pool when OpenBLAS is
   // built with "make USE_OPENMP=0".
@@ -305,9 +305,9 @@ void openblas_fork_handler()
 #endif
 }
 
-extern int openblas_num_threads_env();
-extern int openblas_goto_num_threads_env();
-extern int openblas_omp_num_threads_env();
+extern int openblas_num_threads_env(void);
+extern int openblas_goto_num_threads_env(void);
+extern int openblas_omp_num_threads_env(void);
 
 int blas_get_cpu_number(void){
 #if defined(OS_LINUX) || defined(OS_WINDOWS) || defined(OS_FREEBSD) || defined(OS_OPENBSD) || defined(OS_NETBSD) || defined(OS_DRAGONFLY) || defined(OS_DARWIN) || defined(OS_ANDROID)