Nowadays I have done company works and physical exercise only. Is it right attitude of my life?
Today's lesson: Never underestimate gdb's message.
In a source file, regcomp() segv'ed. What a strange situation! I've spend an hour for googling similar symptoms. But actual cause was double free() in another function.
gdb backtrace showed me that segv was related to memory handling. another gdb backtrace even told me that glibc detected double free. But I overlooked them. OTL