Compilers on command line

The compiler_args generator creates a file named conanbuildinfo.args containing command line arguments to invoke gcc, clang or cl (Visual Studio) compiler.

Now we are going to compile the getting started example using compiler_args instead of the cmake generator.

Open conanfile.txt and change (or add) compiler_args generator:

[requires]
poco/1.9.4

[generators]
compiler_args

Install the requirements (from the mytimer/build folder):

$ conan install ..

Note

Remember, if you don’t specify settings in the install command with -s, Conan will use the detected defaults. You can always change them by editing the ~/.conan/profiles/default or override them with “-s” parameters.

The generated conanbuildinfo.args show:

-DPOCO_STATIC=ON -DPOCO_NO_AUTOMATIC_LIBS
-I/home/user/.conan/data/poco/1.9.4/_/_/package/58080bce1cc38259eb7c282aa95c25aecde8efe4/include
-I/home/user/.conan/data/openssl/1.0.2t/_/_/package/f99afdbf2a1cc98ba2029817b35103455b6a9b77/include
-I/home/user/.conan/data/zlib/1.2.11/_/_/package/6af9cc7cb931c5ad942174fd7838eb655717c709/include
-m64 -O3 -s -DNDEBUG
-Wl,-rpath="/home/user/.conan/data/poco/1.9.4/_/_/package/58080bce1cc38259eb7c282aa95c25aecde8efe4/lib"
-Wl,-rpath="/home/user/.conan/data/openssl/1.0.2t/_/_/package/f99afdbf2a1cc98ba2029817b35103455b6a9b77/lib"
-Wl,-rpath="/home/user/.conan/data/zlib/1.2.11/_/_/package/6af9cc7cb931c5ad942174fd7838eb655717c709/lib"
-L/home/user/.conan/data/poco/1.9.4/_/_/package/58080bce1cc38259eb7c282aa95c25aecde8efe4/lib
-L/home/user/.conan/data/openssl/1.0.2t/_/_/package/f99afdbf2a1cc98ba2029817b35103455b6a9b77/lib
-L/home/user/.conan/data/zlib/1.2.11/_/_/package/6af9cc7cb931c5ad942174fd7838eb655717c709/lib
-lPocoMongoDB -lPocoNetSSL -lPocoNet -lPocoCrypto -lPocoDataSQLite -lPocoData -lPocoZip -lPocoUtil
-lPocoXML -lPocoJSON -lPocoRedis -lPocoFoundation
-lrt -lssl -lcrypto -ldl -lpthread -lz
-D_GLIBCXX_USE_CXX11_ABI=1

This is hard to read, but those are just the compiler_args parameters needed to compile our program:

-I options with headers directories

-L for libraries directories

-l for library names

and so on… see the complete reference here

It’s almost the same information we can see in conanbuildinfo.cmake and many other generators’ files.

Run:

$ mkdir bin
$ g++ ../timer.cpp @conanbuildinfo.args -std=c++14 -o bin/timer

Note

“@conanbuildinfo.args” appends all the file contents to g++ command parameters

$ ./bin/timer
 Callback called after 250 milliseconds.
 ...

To invoke cl (Visual Studio compiler):

$ cl /EHsc timer.cpp @conanbuildinfo.args

You can also use the generator within your build() method of your conanfile.py.

Check the Reference, generators, compiler_args section for more info.