diff --git a/syscall/syscall.csv b/syscall/syscall.csv
index 7d0ef87e72..d4b1c3e38a 100644
--- a/syscall/syscall.csv
+++ b/syscall/syscall.csv
@@ -86,7 +86,7 @@
 "pthread_detach","pthread.h","!defined(CONFIG_DISABLE_PTHREAD)","int","pthread_t"
 "pthread_exit","pthread.h","!defined(CONFIG_DISABLE_PTHREAD)","void","pthread_addr_t"
 "pthread_get_stackaddr_np","pthread.h","!defined(CONFIG_DISABLE_PTHREAD)","void*","pthread_t"
-"pthread_get_stacksize_np","pthread.h","!defined(CONFIG_DISABLE_PTHREAD)","size_t","pthread_t"
+"pthread_get_stacksize_np","pthread.h","!defined(CONFIG_DISABLE_PTHREAD)","ssize_t","pthread_t"
 "pthread_getaffinity_np","pthread.h","!defined(CONFIG_DISABLE_PTHREAD) && defined(CONFIG_SMP)","int","pthread_t","size_t","FAR cpu_set_t*"
 "pthread_getschedparam","pthread.h","!defined(CONFIG_DISABLE_PTHREAD)","int","pthread_t","FAR int*","FAR struct sched_param*"
 "pthread_getspecific","pthread.h","!defined(CONFIG_DISABLE_PTHREAD)","FAR void*","pthread_key_t"