error: use of undeclared identifier 'errno'

[yurivict]

Build fails on FreeBSD 12.3:

/wrkdirs/usr/ports/science/psi4/work/psi4-0889d6d34/psi4/src/psi4/libpsio/rw.cc:86:33: error: use of undeclared identifier 'errno'
        const int saved_errno = errno;
                                ^
/wrkdirs/usr/ports/science/psi4/work/psi4-0889d6d34/psi4/src/psi4/libpsio/rw.cc:97:33: error: use of undeclared identifier 'errno'
        const int saved_errno = errno;
                                ^
/wrkdirs/usr/ports/science/psi4/work/psi4-0889d6d34/psi4/src/psi4/libpsio/rw.cc:119:37: error: use of undeclared identifier 'errno'
            const int saved_errno = errno;
                                    ^
/wrkdirs/usr/ports/science/psi4/work/psi4-0889d6d34/psi4/src/psi4/libpsio/rw.cc:131:37: error: use of undeclared identifier 'errno'
            const int saved_errno = errno;
                                    ^

It looks like #include <errno.h> is missing.

[JonathonMisiewicz]

Why errno.h rather than cerrno?

[yurivict]

Because the manpage says so.

[TiborGY]

Which manpage? The C++ standard seems to suggest <cerrno>, see https://en.cppreference.com/w/cpp/header/cerrno

[yurivict]

man errno suggests it, but <cerrno> should also be ok in C++ code.