diff --git a/src/os/unix/ngx_errno.c b/src/os/unix/ngx_errno.c
index 75176c49a..e787b2377 100644
--- a/src/os/unix/ngx_errno.c
+++ b/src/os/unix/ngx_errno.c
@@ -42,7 +42,7 @@ ngx_strerror(ngx_err_t err, u_char *errstr, size_t size)
 }
 
 
-ngx_uint_t
+ngx_int_t
 ngx_strerror_init(void)
 {
     char       *msg;
diff --git a/src/os/unix/ngx_errno.h b/src/os/unix/ngx_errno.h
index 2912dea04..125087e78 100644
--- a/src/os/unix/ngx_errno.h
+++ b/src/os/unix/ngx_errno.h
@@ -69,7 +69,7 @@ typedef int               ngx_err_t;
 
 
 u_char *ngx_strerror(ngx_err_t err, u_char *errstr, size_t size);
-ngx_uint_t ngx_strerror_init(void);
+ngx_int_t ngx_strerror_init(void);
 
 
 #endif /* _NGX_ERRNO_H_INCLUDED_ */
diff --git a/src/os/win32/ngx_errno.c b/src/os/win32/ngx_errno.c
index f6d947a75..b732bf4b1 100644
--- a/src/os/win32/ngx_errno.c
+++ b/src/os/win32/ngx_errno.c
@@ -53,7 +53,7 @@ ngx_strerror(ngx_err_t err, u_char *errstr, size_t size)
 }
 
 
-ngx_uint_t
+ngx_int_t
 ngx_strerror_init(void)
 {
     return NGX_OK;
diff --git a/src/os/win32/ngx_errno.h b/src/os/win32/ngx_errno.h
index 5b11a65b0..090ba1b53 100644
--- a/src/os/win32/ngx_errno.h
+++ b/src/os/win32/ngx_errno.h
@@ -59,7 +59,7 @@ typedef DWORD                      ngx_err_t;
 
 
 u_char *ngx_strerror(ngx_err_t err, u_char *errstr, size_t size);
-ngx_uint_t ngx_strerror_init(void);
+ngx_int_t ngx_strerror_init(void);
 
 
 #endif /* _NGX_ERRNO_H_INCLUDED_ */