CODEWITHSUNDEEP
c++windowsgcccompilationmingw
user2366975
user2366975

Reputation: 4700

MinGW msys package not found: General advice how to proceed

Every now and then I want to compile something from source with mingw (on windows). I open msys, type ./configure, and it says

checking for...xxxxxx

There I have the first questions:

Occassionally there is an error like 

configure: error: Package requirements <ogg >= 1.3> were not met:
No package 'ogg' found.

Well then I google and find "you can output the default lookup directories" so okay, I type gcc -print-search-dirs and see a list of directories, for example C:/mingw/lib, C:/mingw/lib/gcc, ...

Those folders contain .a-files. And guess what, some of them also contain libogg.a. So why is it complaining? Perhaps the version number? No, I downloaded the newest source and compiled it, and put the .a file into the directories. Same error. It drives me crazy! Please give some advice what to do.

Upvotes: 2

Views: 622

Answers (1)

Mike Kinghan
Mike Kinghan

Reputation: 61272

Traditionally and typically, when a ./configure script checks for a library that the package you are configuring needs to link against, it checks at least for the presence and usability of the library itself and also for the header file(s) of the library, without which the compiler cannot use the library's API. (I say typically, because what any given ./configure check actually does is programmed by the package maintainer. It has nothing to do with your compiler).

Checking for the presence and usability of libfoobar normally does not mean that the ./configure check searches the filesystem for libfoobar.dll, libfoobar.a, or whatever. It means that the ./configure check simply attempts to compile and link a specimen program against libfoobar using the commands that are appropriate for doing so, when libfoobar is installed.

Often too (and increasingly), a ./configure check for a library libfoobar invokes the pkg-config tool to attempt to retrieve the correct compiler and linker flags for use with libfoobar. For this attempt to succeed, a pkg-config meta-data file associated with the library package, foobar.pc, must be found in a standard place in the filesystem, e.g. /usr/lib/pkgconfig, /usr/share/pkgconfig

For the library, plus its headers, plus its pkg-config meta-data (if any) all to be available for ./configure it is necessary to install the development package of libfoobar, as opposed to the basic package. The development package usually has the same name as the basic package with the addition of a -dev or -devel component, e.g. libfoobar-dev

If a ./configure check fails with an error of the form:

No package 'foobar' found.

it means that the check attempted to retrieve pkg-config meta-data for foobar and none was found. That will usually be because the development package libfoobar-dev is not installed, even if libfoobar is.

Upvotes: 1

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