I compiled this code at home on my mac w/ xcode and there was no provblem. I compile it at school with g++ on linux and I get these errors:
numeric_limits’ is not a member of std
expected primary-expression before ‘>’ token
no matching function for call to ‘max()’
#include <iostream>
#include <cstdlib>
using namespace std;
int GetIntegerInput(int lower, int upper)
{
int integer = -1;
do
{
cin >> integer;
cin.clear();
cin.ignore(std::numeric_limits<streamsize>::max(), '\n'); //errors here
} while (integer < lower || integer > upper);
return integer;
}
I'm guessing maybe I have to include an extra header. If I take away the std::
it just gives me a similar error:
numeric_limits
was not declared in this scope
You need to include the header file <limits>
, which is where std::numeric_limits
is defined. Your Mac compiler was helping you out by automatically including that header file; however, you should not rely on that behavior and explicitly include any header files you need.
GCC 11 started to explicitly require including <limits>
, <memory>
, <utility>
, <thread>
according to https://www.gnu.org/software/gcc/gcc-11/porting_to.html#header-dep-changes
The same or similar story is with Clang 12 (or earlier, I don't know).
Since I meet this error (often) while using yarn
(package manager for Node.js) and it overwrites all source files every time, I cannot add #include <limits>
easily: I would need either to fork or spam cp /tmp/fixedBad.h /installdir/bad.h
while compilation is ongoing.
Therefore my solution is to add to CXXFLAGS (not CFLAGS) this:
-include /usr/include/c++/11/limits
(Ubuntu 21.04, gcc 11.1.0)
-include /usr/include/c++/11.1.0/limits
(Arch Linux; same version but path differs from Debian/Ubuntu)
or elegantly: -include /usr/include/c++/11*/limits
Note that *
works only when used by shell (bash, sh, zsh, etc.) or a makefile. In other words, gcc and clang don't pay attention to *
in file paths, so beware if you use ninja build
or directly pass arguments to gcc/clang from e.g. a C program.
I have this in /etc/environment
#CPPFLAGS="-D_FORTIFY_SOURCE=2 -DNDEBUG"
CPPFLAGS="-D_FORTIFY_SOURCE=2"
CFLAGS="-g -pipe -march=native -mtune=native -Ofast -pipe -ftree-vectorize -fstack-protector-strong"
CXXFLAGS="-g -pipe -march=native -mtune=native -Ofast -pipe -ftree-vectorize -fstack-protector-strong -include /usr/include/c++/11*/limits"
LDFLAGS="-Wl,-O1,--sort-common,--as-needed,-z,relro"
RUSTFLAGS="-C target-cpu=native -C opt-level=2"
Check echo $CXXFLAGS
, and if changes aren't applied, restart shell or OS, or logout of the current tty, or switch to another tty, or just run in terminal:
export CXXFLAGS="-g -pipe -march=native -mtune=native -Ofast -pipe -ftree-vectorize -fstack-protector-strong -include /usr/include/c++/11*/limits"
or set -a; source /etc/environment; set +a;
I also tried adding to CXXFLAGS -include '<limits>'
and -include '<limits.h>'
, but it says "No such file or directory"
Also I have another solution (very dirty):
Add this to /usr/include/stdint.h
(or stdlib.h
or some other popular file) before the last line (#endif
):
#ifdef __cplusplus
extern "C++" {
#include <limits>
}
#endif
Ubuntu 21.04's and Debian Buster's dpkg-query -S /usr/include/stdlib.h
says it is owned by libc6-dev:amd64
. Arch Linux's pacman -Qo /usr/include/stdlib.h
says it is owned by glibc
. So this hack will be overwritten when the package updates, don't forget.
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