问题
I somehow lost the man pages for gcc and g++. I'm not sure where/what to look for. I'm pretty sure the man pages used to work some time ago. It also works on my Mac at work where I use roughly the same setup. Could it be a problem with brew? Or is it a bug in the XCode Command Line Tools?
Update: I just tried to re-install the XCode Command Line Tools. No luck.
~
✓ man gcc
No manual entry for gcc
~
✗ which gcc
/usr/bin/gcc
~
✓ gcc --version
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 5.1 (clang-503.0.40) (based on LLVM 3.4svn)
Target: x86_64-apple-darwin13.1.0
Thread model: posix
回答1:
gcc isn't installed anymore by Xcode, it really installs clang and calls it gcc
usxxplayegm1:~ grady$ which gcc
/usr/bin/gcc
usxxplayegm1:~ grady$ /usr/bin/gcc --version
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 5.1 (clang-503.0.38) (based on LLVM 3.4svn)
Target: x86_64-apple-darwin13.0.2
Thread model: posix
you need man clang
I thought it was a symlink, but ls -l doesn't list it as a symlink, so either it is a hard link or some other sort of trickery.
回答2:
Look at how you set MANPATH in your .profile. Instead of, e.g.,
export MANPATH=/opt/local/man:/usr/local/man
you should do
export MANPATH="/opt/local/man:/usr/local/man:$MANPATH"
And then (breathe) open a new Terminal window.
This way your .profile isn't wiping out (or reflecting an old version of) the system's way of setting MANPATH, which is modified when you install (or reinstall) Xcode.
回答3:
I use High Sierra with g++ 7.2 port. Setting MANPATH environment to /opt/local/man (or to /opt/local/man/man1 where g++.gz is found) did not work. So, after ensuring that the soft link g++.gz points to g++-mp-7.1.gz (there was not a g++-mp-7.2.gz in the man1 directory though g++7.2 is my version), I always use the command:
man /opt/local/share/man/man1/g++.gz
that never fails. You can store an alias for this in your .profile, if you are frequently using the man command for g++.
来源：https://stackoverflow.com/questions/23684642/how-to-fix-no-manual-entry-for-gcc