Add tng_num_frames_get() to get the number of frames in the trajectory. Added to reading example as well.

1 files changed, 15 insertions, 1 deletions

diff --git a/src/tests/tng_io_read_pos.c b/src/tests/tng_io_read_pos.c
index af5e828..493e10e 100644
--- a/src/tests/tng_io_read_pos.c
+++ b/src/tests/tng_io_read_pos.c
@@ -21,7 +21,7 @@ int main(int argc, char **argv)
 {
     tng_trajectory_t traj;
     union data_values ***positions = 0; // A 3-dimensional array to be populated
-    int64_t n_particles, n_values_per_frame, n_frames;
+    int64_t n_particles, n_values_per_frame, n_frames, tot_n_frames;
     tng_data_type data_type;
     int i, j;
     int64_t particle = 0;
@@ -63,6 +63,20 @@ int main(int argc, char **argv)
         }
     }
 
+    if(tng_num_frames_get(traj, &tot_n_frames) != TNG_SUCCESS)
+    {
+        printf("Cannot determine the number of frames in the file\n");
+        tng_trajectory_destroy(&traj);
+        exit(1);
+    }
+
+    printf("%"PRId64" frames in file\n", tot_n_frames);
+
+    if(last_frame > tot_n_frames - 1)
+    {
+        last_frame = tot_n_frames - 1;
+    }
+
     n_frames = last_frame - first_frame + 1;
 
     if(tng_atom_name_of_particle_nr_get(traj, particle, atom_name,