/*
* Read the trace by `exec()ing` the provided viewer program if any. If
* `opt_viewer` is NULL, try to read the trace with the default trace reader.
* On success, this function doesn't return.
* Returns -1 if the `opt_viewer` string or the default trace viewer can't be
* `exec()`.
/*
* Read the trace by `exec()ing` the provided viewer program if any. If
* `opt_viewer` is NULL, try to read the trace with the default trace reader.
* On success, this function doesn't return.
* Returns -1 if the `opt_viewer` string or the default trace viewer can't be
* `exec()`.