GDB@wiki（GNU Debugger）
GDB is a portable debugger that runs on many Unix-like systems and works for many programming languages.
SIGFPE
- FPE: floating-point exception.
The SIGFPE signal is sent to a process when it executes an erroneous arithmetic operation, such as division by zero.
被零除 就是一個(gè)典型的 SIGFPE。
all1-all2可能為零
確保不被零除 - C Programming Tutorial: Logical Operators;
Terminate (core dump)蛮艰，Erroneous arithmetic operation
