diff --git a/src/g2c_interface.F90 b/src/g2c_interface.F90
index 05c145ca..e9e838fc 100644
--- a/src/g2c_interface.F90
+++ b/src/g2c_interface.F90
@@ -34,7 +34,7 @@ function g2c_inq_msg(g2id, msg_num, discipline, num_fields, &
           num_local, center, subcenter, master_version, local_version) bind(c)
        use iso_c_binding
        integer(c_int), value :: g2id
-       integer(c_int), intent(in) :: msg_num
+       integer(c_int), value :: msg_num
        integer(c_signed_char), intent(out) :: discipline
        integer(c_int), intent(out) :: num_fields, num_local
        integer(c_short), intent(out) :: center, subcenter
diff --git a/src/g2cf.F90 b/src/g2cf.F90
index 4e7a3962..a35a1194 100644
--- a/src/g2cf.F90
+++ b/src/g2cf.F90
@@ -160,7 +160,8 @@ end function g2cf_inq
   !> Learn about a message are in a GRIB2 file.
   !>
   !> @param[in] g2id The ID of the open file
-  !> @param[in] msg_num The number of message to learn about.
+  !> @param[in] msg_num The number of message to learn about. The
+  !> first message in the file is number 1.
   !> @param[out] discipline The discipline of the message.
   !> @param[out] num_fields Number of fields in the message.
   !> @param[out] num_local Number of local sections in the message.
@@ -179,10 +180,10 @@ function g2cf_inq_msg(g2id, msg_num, discipline, num_fields, &
     implicit none
     
     integer, intent(in) :: g2id, msg_num
-    integer, intent(out) :: discipline
+    integer(kind = 1), intent(out) :: discipline
     integer, intent(out) :: num_fields, num_local
     integer(kind = 2), intent(out) :: center, subcenter
-    integer(kind = 2), intent(out) :: master_version, local_version
+    integer(kind = 1), intent(out) :: master_version, local_version
     integer :: status
 
     integer(c_int) :: cg2id, cmsg_num, cstatus
@@ -192,7 +193,8 @@ function g2cf_inq_msg(g2id, msg_num, discipline, num_fields, &
     integer(c_signed_char) :: cmaster_version, clocal_version
 
     cg2id = g2id
-    cmsg_num = msg_num
+    ! Subtract 1 because C is zero-based.
+    cmsg_num = msg_num - 1 
     cstatus = g2c_inq_msg(cg2id, cmsg_num, cdiscipline, cnum_fields, &
          cnum_local, ccenter, csubcenter, cmaster_version, clocal_version)
     discipline = cdiscipline
diff --git a/tests/test_g2cf.F90 b/tests/test_g2cf.F90
index 474d3da9..d0c205a9 100644
--- a/tests/test_g2cf.F90
+++ b/tests/test_g2cf.F90
@@ -15,7 +15,7 @@ program test_g2cf
   integer :: ierr
 
   print *, 'Testing g2cf API...'
-  ierr = g2cf_set_log_level(1)
+  !ierr = g2cf_set_log_level(1)
 
   ! Open the test file.
   ierr = g2cf_open(fileName, 0, g2cid)
@@ -29,6 +29,8 @@ program test_g2cf
   ! Check the last message.
   ierr = g2cf_inq_msg(g2cid, 19, discipline, num_fields, num_local, center, subcenter, &
        master_version, local_version)
+  if (ierr .ne. 0) stop 100
+  !print *, discipline, num_fields, num_local, center, subcenter, master_version, local_version
   if (discipline .ne. 10 .or. num_fields .ne. 1 .or. num_local .ne. 0 .or. center .ne. 7 .or. &
        subcenter .ne. 0 .or. master_version .ne. 2 .or. local_version .ne. 1) stop 12