Specify C and C++ compiler paths when building Ruby gem - ruby

gem allows specifying build arguments, however I can't find a build argument to override the CC and CXX constants in the Makefile generated by mkmf (the defaults appear to come from RbConfig::CONFIG).
How can I specify which compiler to use when building an extension?

Related

Configure compilation options and compiler autoconf

I'm working on a personal project with Rust and tcl but i still want to use the classic makefile structure.
I know that to compile multifile I just need to declare mod second on main.rs and rustc automatically connect the modules. So I use
$ rustc main.rs -o output -C debuginfo=2
Now I tried to integrate autoconf and automake because I want to make a configure script to check for tcl, rustup etc... But I don't know how to edit to compile with rustc and its options insead of cc and c options (like trying a .o that doesn't compile because they don't have a main function).
for the configure.ac i used:
AC_CONFIG_SRCDIR([source/main.rs])
AC_CONFIG_AUX_DIR(config)
# I manually checked for rustup and tclsh
AM_INIT_AUTOMAKE
AC_CONFIG_FILES([Makefile])
AC_OUTPUT
for the Makefile.am:
AUTOMAKE_OPTIONS = foreign
bin_PROGRAMS = output
SUBDIRS = sources
output_SOURCES = sources/main.rs
I have the main directory with configure.ac and Makefile.am and the sources directory with all the stuff (and also the config directory for autoconf)
Now I tried to integrate autoconf and automake because I want to make a configure script to check for tcl, rustup etc...
The configure script is the responsibility of Autoconf. It is not obligatory to use Automake together with Autoconf, and you should consider whether it would be sensible for you to use Autoconf alone. That would give you complete control over the generated Makefile, as you would write a Makefile.in directly instead of relying on Automake to do that for you. Presumably, you would write a much simpler Makefile.in than Automake generates, and that's fine.
Automake is not necessarily out of the question, but its manual has this to say about language support:
Automake currently only includes full support for C, C++ (see C++
Support), Objective C (see Objective C Support), Objective C++ (see
Objective C++ Support), Fortran 77 (see Fortran 77 Support), Fortran
9x (see Fortran 9x Support), and Java (see Java Support with gcj).
There is only rudimentary support for other languages, support for
which will be improved based on user demand.
Some limited support for adding your own languages is available via
the suffix rule handling (see Suffixes).
The referenced section about suffix rules shows how you might use such a rule to teach Automake how to build Rust programs. It might look something like this:
.rs:
$(RUSTC) $< -o $# $(AM_RUSTFLAGS) $(RUSTFLAGS)
SUFFIXES = .rs
That assumes that configure will identify the Rust compiler and export its name as RUSTC. AM_RUSTFLAGS is for defining compilation flags internally in your project (typically in your Makefile.am), and RUSTFLAGS is for the builder to add or override compilation flags at build time.
But since the compiler does not produce intermediate object files (or so I gather), I would expect that defining sources in output_SOURCES would not yield a working Makefile, and that you would probably need the name of the top-level Rust source to match the name of the wanted binary (i.e. output.rs instead of main.rs). The single-suffix rule should, then, get your binary built without any sources being explicitly specified. You would also want to name all contributing Rust sources in the EXTRA_SOURCES variable, else they would be omitted from distribution packages built via make dist.
Note, too, that the above does not define all the build dependencies that actually exist if you're building multifile programs. I would suggest doing that by adding an appropriate prerequisite-only rule, such as
output: $(output_extra_sources)
(with no recipe) in multifile cases. This will ensure that make will recognize when output needs to be rebuilt as a result of a modification to one of its sources other than output.rs.

Why do I get linker errors when I build a CMake project using Drake, but I can clearly see the symbols?

I have followed the Installation and Quickstart instructions, and am writing a CMake project to use Drake.
I'm looking at a unittest that builds in Drake, run it, and it builds, runs, and passes. However, when I try to use some of that functionality in my CMake project, I get a linker error, such as:
undefined reference to `RigidBodyTree<double>::get_position_name(int) const'
If I look at symbols in the Drake shared library (e.g. nm -C or objdump -TC with grep), I see the signature RigidBodyTree<double>::get_position_name[abi:cxx11](int). However, if I look in the produced object code (which causes the linking to fail), I see RigidBodyTree<double>::get_position_name(int).
(Note: This post is a means to migrate from http://drake.mit.edu/faq.html to StackOverflow for user-based questions.)
This is most likely due to an incompatibilty between the compiler used to produce Drake (e.g. clang) and the compiler that CMake has selected (e.g. gcc-4.9). Specifically, gcc-4.9 or before does not tend to handle the DualABI well when linking against clang-compiled code (ref). You may be able to use other functions, because only functions that return an ABI-dependent class (e.g. std::string) are tagged with the ABI that they are using (since they cannot be distinguished in the function signature).
The fix is to change the compiler CMake is using. One way to do this is to set the CC and CXX environment variables to use a supported compiler. For a list of supported compilers, see Supported Configurations. If you are using pre-compiled binaries, please refer to Binary Packages for the compilers used.
WARNING: Do NOT change the compiler using update-alternatives in Ubuntu, as this may affect your DKMS module compatibility with the kernel (among other things) (ref).

How to build Sqlite binaries in Debug/Release mode

How can we build the SQLite binary in Debug or Release mode?
I have downloaded the source code (sqlite-autoconf-3120000.tar.gz) from https://www.sqlite.org/download.html. Configure file provided by it doesnot support --enable-debug option.
Result of ./configure --help is as follows:
anshu#vijayakumart:~/Git/sqlite-autoconf-3120000$ ./configure --help
`configure' configures sqlite 3.12.0 to adapt to many kinds of systems.
Usage: ./configure [OPTION]... [VAR=VALUE]...
To assign environment variables (e.g., CC, CFLAGS...), specify them as
VAR=VALUE. See below for descriptions of some of the useful variables.
Defaults for the options are specified in brackets.
Configuration:
-h, --help display this help and exit
--help=short display options specific to this package
--help=recursive display the short help of all the included packages
-V, --version display version information and exit
-q, --quiet, --silent do not print `checking ...' messages
--cache-file=FILE cache test results in FILE [disabled]
-C, --config-cache alias for `--cache-file=config.cache'
-n, --no-create do not create output files
--srcdir=DIR find the sources in DIR [configure dir or `..']
Installation directories:
--prefix=PREFIX install architecture-independent files in PREFIX
[/usr/local]
--exec-prefix=EPREFIX install architecture-dependent files in EPREFIX
[PREFIX]
By default, `make install' will install all the files in
`/usr/local/bin', `/usr/local/lib' etc. You can specify
an installation prefix other than `/usr/local' using `--prefix',
for instance `--prefix=$HOME'.
For better control, use the options below.
Fine tuning of the installation directories:
--bindir=DIR user executables [EPREFIX/bin]
--sbindir=DIR system admin executables [EPREFIX/sbin]
--libexecdir=DIR program executables [EPREFIX/libexec]
--sysconfdir=DIR read-only single-machine data [PREFIX/etc]
--sharedstatedir=DIR modifiable architecture-independent data [PREFIX/com]
--localstatedir=DIR modifiable single-machine data [PREFIX/var]
--libdir=DIR object code libraries [EPREFIX/lib]
--includedir=DIR C header files [PREFIX/include]
--oldincludedir=DIR C header files for non-gcc [/usr/include]
--datarootdir=DIR read-only arch.-independent data root [PREFIX/share]
--datadir=DIR read-only architecture-independent data [DATAROOTDIR]
--infodir=DIR info documentation [DATAROOTDIR/info]
--localedir=DIR locale-dependent data [DATAROOTDIR/locale]
--mandir=DIR man documentation [DATAROOTDIR/man]
--docdir=DIR documentation root [DATAROOTDIR/doc/sqlite]
--htmldir=DIR html documentation [DOCDIR]
--dvidir=DIR dvi documentation [DOCDIR]
--pdfdir=DIR pdf documentation [DOCDIR]
--psdir=DIR ps documentation [DOCDIR]
Program names:
--program-prefix=PREFIX prepend PREFIX to installed program names
--program-suffix=SUFFIX append SUFFIX to installed program names
--program-transform-name=PROGRAM run sed PROGRAM on installed program names
System types:
--build=BUILD configure for building on BUILD [guessed]
--host=HOST cross-compile to build programs to run on HOST [BUILD]
Optional Features:
--disable-option-checking ignore unrecognized --enable/--with options
--disable-FEATURE do not include FEATURE (same as --enable-FEATURE=no)
--enable-FEATURE[=ARG] include FEATURE [ARG=yes]
--enable-silent-rules less verbose build output (undo: "make V=1")
--disable-silent-rules verbose build output (undo: "make V=0")
--disable-largefile omit support for large files
--enable-dependency-tracking
do not reject slow dependency extractors
--disable-dependency-tracking
speeds up one-time build
--enable-shared[=PKGS] build shared libraries [default=yes]
--enable-static[=PKGS] build static libraries [default=yes]
--enable-fast-install[=PKGS]
optimize for fast installation [default=yes]
--disable-libtool-lock avoid locking (might break parallel builds)
--enable-editline use BSD libedit
--enable-readline use readline
--enable-threadsafe build a thread-safe library [default=yes]
--enable-dynamic-extensions
support loadable extensions [default=yes]
--enable-fts5 include fts5 support [default=no]
--enable-json1 include json1 support [default=no]
--enable-static-shell statically link libsqlite3 into shell tool
[default=yes]
Optional Packages:
--with-PACKAGE[=ARG] use PACKAGE [ARG=yes]
--without-PACKAGE do not use PACKAGE (same as --with-PACKAGE=no)
--with-pic[=PKGS] try to use only PIC/non-PIC objects [default=use
both]
--with-aix-soname=aix|svr4|both
shared library versioning (aka "SONAME") variant to
provide on AIX, [default=aix].
--with-gnu-ld assume the C compiler uses GNU ld [default=no]
--with-sysroot[=DIR] Search for dependent libraries within DIR (or the
compiler's sysroot if not specified).
Some influential environment variables:
CC C compiler command
CFLAGS C compiler flags
LDFLAGS linker flags, e.g. -L<lib dir> if you have libraries in a
nonstandard directory <lib dir>
LIBS libraries to pass to the linker, e.g. -l<library>
CPPFLAGS (Objective) C/C++ preprocessor flags, e.g. -I<include dir> if
you have headers in a nonstandard directory <include dir>
LT_SYS_LIBRARY_PATH
User-defined run-time library search path.
CPP C preprocessor
Use these variables to override the choices made by `configure' or to help
it to find libraries and programs with nonstandard names/locations.
Is there any way to specify Debug/Release mode while generating binaries?
Compilation options must be defined as preprocessor symbols:
configure CPPFLAGS=-DSQLITE_DEBUG

Is there a way to reference a library in Automake?

I'm trying to use LDADD to reference a prebuilt library and Automake insists that the library has to be built. The Automake manual says:
"If you need to link against libraries that are not found by configure, you can use LDADD to do so. This variable is used to specify additional objects or libraries to link with; it is inappropriate for specifying specific linker flags, you should use AM_LDFLAGS for this purpose."
In my code I have used both
LDADD = ../lib/library.a
and
prog_LDADD = ../lib/librarya.
In both cases make outputs
*** No rule to make target 'library.a', needed by 'SlipTest.exe'. Stop.
It's got me stumped.
art
check whether the file ../lib/library.a actually exists.
when building libraries with automake you should use libtool, and libtool-libraries use the (platform independent) .la extension:
prog_LDADD = ../lib/library.la

How to Statically Link External Libraries when Compiling a Ruby C Extension

I am building a Ruby C Extension on Windows which requires some external C libraries, specifically libcurl and its dependancies. I have the curllib dll's and .a files. However when I build with extconf.rb it always links the libraries dynamically which requires someone to have curl installed and in their windows path to use the compiled extension. Instead I want extconf.rb to link curl and its dependancies statically so that anyone can use the extension on windows without having to add curllib to their path first.
This is my extconf.rb
require 'mkmf'
# Name the extension.
extension_name = 'ConnectionManager'
dir_config("curl")
# Make sure the cURL library is installed.
have_library("curl")
# Create the Makefile.
create_makefile(extension_name)
This is the command I am generating my makefile with
ruby extconf.rb --with-curl-dir=C:/Knapsack/x86-windows
Is there something that I can add to my extconf.rb file or command to force ruby to link the external libraries to my c extension statically? Any help would be appreciated and please let me know if you need any more information.
I had a similar problem writing a native extension using gif_lib on linux.
Try adding the following to your extconf.rb:
unless find_library("curl", "curl_version")
abort "curl is not installed, please install and try again"
end
The find_library function returns true if the library and entry point are present and has the side effect of adding it to the -l option to gcc.
I found these links useful:
http://tenderlovemaking.com/2010/12/11/writing-ruby-c-extensions-part-2.html
Here is the C extension (a working example):
https://github.com/e-g-r-ellis/ruby-giflib
When I built my Ruby C Extension using nmake from Visual Studio Express I had to change compiler flag from -MD to -MT in order to avoid dependency on MSVCRT.
I set the $CFLAGS variable in my extconf.rb file.
$CFLAGS = '-MT -Ot -Ox -W4' Not sure if it's the correct way to modify these flags, but it worked.
https://bitbucket.org/thomthom/sketchup-ruby-c-extension/commits/3e87351be87f177b8ed43798587f6e798064492d

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