Which ROOT version?
Note: ROOT 6 returns “Double_t” peaks’ positions, while ROOT 5 returns “Float_t” peaks’ positions.
Try something like this: // ...
#if ROOT_VERSION_CODE >= ROOT_VERSION(6,00,00)
Double_t *xpeaks; // ROOT 6
#else
Float_t *xpeaks; // ROOT 5
#endif
xpeaks = s->GetPositionX();
for (p = 0; p < nfound; p++) {
Double_t xp = xpeaks[p]; // ROOT 6 or 5
// ...
}
// ... See also: Illegal pointer to class object back 0x0 165