https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100751 --- Comment #19 from Gejoe <gejoed at rediffmail dot com> --- Just to add on : The a.out was run twice and hence the value of 20 against line # 19, 29 of .c.gcov file(as shown in commment #16). Let me know if anything is not clear.