ming32-make使用g ++而不是cc或gcc来编译.c源文件

Question

I recently installed mingw-w64 to learn c without needing cygwin. The issue is that mingw32-make is using g++ to compile my .c source, but I don't really know why. The behavior is illustrated here:

here's the source:

#include <stdio.h>
int main(int argc, char *argv[])
{
    puts("Hello world.");
    return 0;
}

here's the makefile:

CC = gcc -O
CFLAGS=-Wall -g
clean:
    rm -f hello_world

using gnuwin32 version of make:

-> make hello_world
gcc -O -Wall -g    hello_world.c   -o hello_world

using mingw32-make:

-> mingw32-make hello_world
g++     hello_world.c   -o hello_world

Can someone explain this, or know why its happening? Using Cygwin, and also using Linux, the make tool uses a c-compiler (usually cc) as expected. Why does mingw32-make use g++, instead of gcc. gcc is installed in the bin directory.

mingw-w64 is the latest winbuild as of 2 days ago

Answer 1

mingw32-make (correctly IMO) treats the file system as case insensitive, so foo.c and FOO.C refer to the same file.

Your makefile lacks any explicit rule for your hello_world goal, so built-in implicit rules must be used; it seems that the COMPILE.C rule is being matched for hello_world.c, before the COMPILE.c rule; COMPILE.C is a default rule for compiling C++, so the appropriate compiler is used.

As you note, setting CXX = gcc is kludgy, and fundamentally wrong; it will break if your project expands to requiring mixed C and C++ components. A more appropriate solution is to provide your own rule ... either an explicit rule, or a pattern rule, to direct mingw32-make to use $(CC) for compiling *.c (and *.C) files, so that the built-in default rules will not apply. You can then keep CXX = g++ for compiling any *.cpp files, (recommended for compatibility with MSVC convention), which your project may include.

Answer 2

This has been confirmed to be a problem inside GNU Make, present in builds that enabled the case-insensitive filesystem option. It has also been fixed in the repository.

The solution is either to use a GNU Make build that doesn't have the case-insensitve filesystem option ( --enable-case-insensitive-file-system / HAVE_CASE_INSENSITIVE_FS ) enabled, or using the latest sources ( this revision or newer), where the issue is fixed.

Further references:

• https://savannah.gnu.org/bugs/index.php?46304
• https://github.com/niXman/mingw-builds/issues/413