Slackware 13.37
Compiling 2 apps from source this morning. Both failed with essentially the same error3 questions:
1. Is there any particular reason why it does not recommend simply installing 'sigc++-2.0'?
2. What is a "non-standard prefix" with reference to PKG_CONFIG_PATH? When installing software I always use the default paths set by slackware.
3. Neither libsigc_CFLAGS nor libsigc_LIBS are mentioned in "man pkg-config", and even if they were, do I really want "to avoid the need to call pkg-config"? There would seem to be a whole lot of unstated consequences to such an action.

Slack doesn't work that way. It leaves it up to you to resolve your dependencies. You will need to install sigc++ either from compiling from source, or through sbopkg by searching for libsigc.

http://slackbuilds.org/repository/13...ies/libsigc++/

Slackbuilds.org should your first port of call to look for dependencies.

1 members found this post helpful.

Thank you for your responses, but I really wanted answers to the 3 questions I asked.

1) That would be up to the developers of the source code. Sometimes you get a message and on rare occasions a link to the dep's website. Sometimes the README or INSTALL file have that info too. A lot of the time though, we are left in the dark until an error pops up like yours above.

2) Well you can install software anywhere, but what it is suggesting is if that is the case then you need to point that out during the configure or via PKG_CONFIG_PATH variable. It's a pretty standard message to get now. It means basically that it can't find sigc++ in the places that pkg-config knows about.

3) If I understand you correctly, usually make will call pkg-config during the compile anyway. If there are problems you may want to have a look yourself to see exactly what it's outputting. I've had problems when make doesn't seem to get the correct info (or doesn't even use pkg-config) and I've had to add a -I or -l in the CFLAGS of a slackbuild manually.

2 members found this post helpful.

Many thanks. Not being a programmer I have only the vaguest notion of what goes on in
./configure
make
make install
Which is fine when the process goes without a hitch. But when it doesn't, the information given by the process is often obscure.

Thanks Dive.

However, per the slackbuilds.org guidelines, I believe that any dependencies that a slackbuild requires are supposed to be mentioned in the package descriptions requirements.

Although libtorrent is mentioned, libsig++ is not. (Its a keyword, but it should be listed on the bottom along the requirements.)

1. 'why it does not recommend...': Package requirements (sigc++-2.0) were not met
2. Standard prefix would be either /usr/local or /usr. pkg-config will only look there unless you tell it to look elsewhere by setting PKG_CONFIG_PATH.
3. Neither libsigc_CFLAGS nor libsigc_LIBS are mentioned ... The installation of libsigc++ will install the libsigc++.pc file which pkg-config then finds when trying to compile something which requires libsigc++ and thereby set libsigc_CFLAGS and libsigc_LIBS.