[英]g++ variable size array no warning?
int a;
cin >> a;
int ints[a];
Why does this not throw any kind of warning while compiling?为什么这在编译时不会抛出任何警告? How do I know when this array thing is actually using the heap or the stack?我怎么知道这个数组实际上是在使用堆还是堆栈?
g++ -std=c++11 -Wall *.cpp -o main
ISO C++ disallows the use of variable length arrays , which g++
happily tells you if you increase the strictness of it by passing it the -pedantic
flag. ISO C++ 不允许使用变长数组,如果您通过向它传递-pedantic
标志来增加它的严格性, g++
高兴地告诉您。
Using -pedantic
will issue a warning about things breaking the standard.使用-pedantic
将发出有关违反标准的警告。 If you want g++
to issue an error and with this refuse compilation because of such things;如果您希望g++
发出错误并因此拒绝编译; use -pedantic-errors
.使用-pedantic-errors
。
g++ -Wall -pedantic -std=c++11 apa.cpp
apa.cpp: In function ‘int main(int, char**)’:
apa.cpp:8:13: warning: ISO C++ forbids variable length array ‘ints’ [-Wvla]
int ints[a];
^
apa.cpp:8:7: warning: unused variable ‘ints’ [-Wunused-variable]
int ints[a];
^
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