mt19937 is not a member of std possible makefile issue

Question

In my program I use std::mt19937 to generate random numbers. On two systems (latest windows and ubuntu) the program compiles fine. But, on a third unknown system (using make) I get the error message: " 'mt19937' is not a member of 'std' "

I am assuming the makefile isn't written correctly. I am new to makefiles and not sure where to start. Do I need to enforce c++11? How would I do so?

all:

%.o: %.cc
    g++ -c -O2 -Wall -Wextra -pedantic $<

library-objects = \
    BigUnsigned.o \
    BigInteger.o \
    BigIntegerAlgorithms.o \
    BigUnsignedInABase.o \
    BigIntegerUtils.o \

library-headers = \
    NumberlikeArray.hh \
    BigUnsigned.hh \
    BigInteger.hh \
    BigIntegerAlgorithms.hh \
    BigUnsignedInABase.hh \
    BigIntegerLibrary.hh \

library: $(library-objects)

$(library-objects): $(library-headers)

# Components of the program.
program = rsa435
program-objects = rsa435.o

$(program-objects) : $(library-headers)

$(program) : $(program-objects) $(library-objects)
    g++ $^ -o $@

clean :
    rm -f $(library-objects) $(testsuite-cleanfiles) $(program-objects) $(program)

all : library $(program)

EDIT: It might be worth mentioning that I have both cc files and cpp files. Maybe this is causing an issue as well?

Definitely the top one (that's the compilation stage). Not sure about the bottom one (that's the link stage). Try both unless you get an error. — Richard Critten, Feb 27 '17 at 13:20
cc and cpp are both extensions for files containing C++ source code: http://stackoverflow.com/q/1545080/1025391 — moooeeeep, Feb 27 '17 at 13:24
Richard Critten means: g++ -c -std=c++11 -O2 -Wall -Wextra -pedantic $ — hannibal, Feb 27 '17 at 13:29
I always recommend setting the compiler variable `$CXX` to `clang++ -std=c++11 -stdlib=libc++`, since these affect both compilation *and* linking. Use that variable in your Makefile rather than hard coding options. Don't use the system `g++` (although I think it's a `clang` wrapper with an older std library these days). Install a Macport or Homebrew `gcc` for OS X if you want to use `g++`. — Brett Hale, Feb 27 '17 at 14:45
@BrettHale let the default `CXX` is better and don't add option directly to `CXX` but in `CXXFLAGS`. — Stargateur, Feb 27 '17 at 18:23
@Stargateur - no, it isn't. Because $CXXFLAGS is not picked up by the linker. Dialect options properly belong in $CXX. — Brett Hale, Feb 27 '17 at 19:50
@BrettHale Again I disagree, linker flag generally belong in `LDFLAGS`. — Stargateur, Feb 27 '17 at 20:08

vharron · Answer 1 · 2017-07-26T22:29:57.193

3

The error is saying is that it knows about the "std" namespace but there is no "mt19937" defined in that namespace.

Add "-std=c++11" to your g++ command line because mt19937 wasn't defined until C++11.

(Credit: this was originally posted by Richard Critten as a comment to the question.)

Also, you might need to add this header file:

#include <random>

edited Jul 26 '17 at 22:29

answered Jul 26 '17 at 22:24

vharron

1,138
11
20

score 2 · Answer 2 · answered Jan 14 '20 at 08:55

2

"-std=c++11" is not enough , add #include<bits/stdc++.h>

answered Jan 14 '20 at 08:55

Adel Ben Hamadi

720
10
13

mt19937 is not a member of std possible makefile issue

2 Answers2