net-snmp @5.8: error: implicit declaration of function 'get_in_address' is invalid in C99

[Prolixium]

From what I can tell on a fresh install of macOS Big Sur (11.0.1) and Xcode 12.2 w/MacPorts 2.6.4, net-snmp 5.8 fails to compile:

/bin/sh ../../libtool  --mode=compile /usr/bin/clang -I../../include -I. -I../../agent -I../../agent/mibgroup  -I../../snmplib -I/opt/local/include -I/opt/local/include -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX11.0.sdk  -pipe -Os -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX11.0.sdk -arch x86_64 -DNETSNMP_ENABLE_IPV6 -fno-strict-aliasing -DNETSNMP_REMOVE_U64 -pipe -Os -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX11.0.sdk -arch x86_64 -Udarwin20 -Ddarwin20=darwin20  -c -o mibII/ipAddr.lo mibII/ipAddr.c
mibgroup/mibII/ipAddr.c:200:29: error: variable has incomplete type 'struct in_ifaddr'
    static struct in_ifaddr in_ifaddr, lowin_ifaddr;
                            ^
mibgroup/mibII/ipAddr.c:200:19: note: forward declaration of 'struct in_ifaddr'
    static struct in_ifaddr in_ifaddr, lowin_ifaddr;
                  ^
mibgroup/mibII/ipAddr.c:200:40: error: variable has incomplete type 'struct in_ifaddr'
    static struct in_ifaddr in_ifaddr, lowin_ifaddr;
                                       ^
mibgroup/mibII/ipAddr.c:200:19: note: forward declaration of 'struct in_ifaddr'
    static struct in_ifaddr in_ifaddr, lowin_ifaddr;
                  ^
mibgroup/mibII/ipAddr.c:204:25: error: variable has incomplete type 'struct ifnet'
    static struct ifnet ifnet;
                        ^
mibgroup/mibII/ipAddr.c:204:19: note: forward declaration of 'struct ifnet'
    static struct ifnet ifnet;
                  ^
mibgroup/mibII/var_route.c:195:29: error: implicit declaration of function 'get_in_address' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
            cp = (u_char *) get_in_address((struct sockaddr *) (rtp + 1),
                            ^
3 errors generated.
mibgroup/mibII/var_route.c:195:18: warning: cast to 'u_char *' (aka 'unsigned char *') from smaller integer type 'int' [-Wint-to-pointer-cast]
            cp = (u_char *) get_in_address((struct sockaddr *) (rtp + 1),
                 ^
mibgroup/mibII/var_route.c:235:27: error: implicit declaration of function 'get_in_address' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
        return (u_char *) get_in_address((struct sockaddr *) (rtp + 1),
                          ^
mibgroup/mibII/var_route.c:235:16: warning: cast to 'u_char *' (aka 'unsigned char *') from smaller integer type 'int' [-Wint-to-pointer-cast]
        return (u_char *) get_in_address((struct sockaddr *) (rtp + 1),
               ^
mibgroup/mibII/var_route.c:269:13: warning: cast to 'u_char *' (aka 'unsigned char *') from smaller integer type 'int' [-Wint-to-pointer-cast]
        return (u_char *) get_in_address((struct sockaddr *) (rtp + 1),
               ^
mibgroup/mibII/var_route.c:299:20: warning: cast to 'u_char *' (aka 'unsigned char *') from smaller integer type 'int' [-Wint-to-pointer-cast]
            return (u_char *) get_in_address((struct sockaddr *) (rtp + 1),
                   ^
mibgroup/mibII/var_route.c:2110:1: error: conflicting types for 'get_in_address'
get_in_address(const void *ap, int addresses, int wanted)
^
mibgroup/mibII/var_route.c:195:29: note: previous implicit declaration is here
            cp = (u_char *) get_in_address((struct sockaddr *) (rtp + 1),
                            ^
4 warnings and 3 errors generated.

If I'm reading the port summary page correctly, there might not be a working build for Catalina either, and Mojave was the last OS where the port built successfully.

I'm attaching net-snmp-build.txt that shows all the messages from the failed build.

Please let me know if there's anything I should try or anything additional I can include in this ticket. Thanks!

[Prolixium]

build text

[ryandesign (Ryan Schmidt)]

The port summary page is not the final word on whether a port built or not. We do have net-snmp packages available for all OS versions up to and including Catalina; see ​https://packages.macports.org/net-snmp/

This is the well-known Xcode 12 implicit function declaration issue.

[kencu (Ken)]

FYI even when I disabled the implicit function issue, it would not build due to this:

error: variable has incomplete type 'struct in_ifaddr'

[ryandesign (Ryan Schmidt)]

As far as I recall, that error message is also indicative of forgetting to include the right header.

[kencu (Ken)]

oh, that would be great then.

[miken32 (Michael Newton)]

Is there anything we can do to help resolve this issue? Any patches to test, or upstream bugs to file? I'm not a C programmer, but my understanding is this function just needs to be pre-declared either at the top of the file or in a header file. Since it violates current C standards, it seems like it's a no-brainer to just add it to the header but I assume there's some drawback?

[amake (Aaron Madlon-Kay)]

I have an incomplete PR up to bump the version and fix the build, but the last mile is unfortunately beyond my current abilities: ​https://github.com/macports/macports-ports/pull/9506

If someone could help out that would be great.

[Aaron Madlon-Kay <amake@…>]

In 4c628cac76d0e5ee79c3bbe8c6679ca7f627b064/macports-ports (master):

net-snmp: update to 5.9 (​https://github.com/macports/macports-ports/pull/9506)

Fixes #61624