ca-gateway doesn't compile on macOS mojave

[vodellv]

I get the following error message:
mac-130048:gateway2_0_6_0 odell$ make
/Library/Developer/CommandLineTools/usr/bin/make -C ./configure install
/Library/Developer/CommandLineTools/usr/bin/make -C O.darwin-x86 -f ../Makefile TOP=../..
T_A=darwin-x86 install
perl -CSD /Users/odell/base-3.15.7/bin/darwin-x86/convertRelease.pl checkRelease
/Library/Developer/CommandLineTools/usr/bin/make -C ./src install
/Library/Developer/CommandLineTools/usr/bin/make -C O.darwin-x86 -f ../Makefile TOP=../..
T_A=darwin-x86 install
c++ -DUNIX -Ddarwin -O3 -g -Wall -DSTAT_PVS -DRATE_STATS -DCONTROL_PVS -DCAS_DIAGNOSTICS -DHANDLE_EXCEPTIONS -DUSE_DENYFROM -arch x86_64 -fno-common -I. -I../O.Common -I. -I. -I.. -I../../include/compiler/clang -I../../include/os/Darwin -I../../include -I/Users/odell/base-3.15.7/include/compiler/clang -I/Users/odell/base-3.15.7/include/os/Darwin -I/Users/odell/base-3.15.7/include -I/Users/odell/base-3.15.7/src/cas/generic -I/Users/odell/base-3.15.7/src/ca/legacy/pcas/generic -c ../gatePv.cc
In file included from ../gatePv.cc:71:
../gateAs.h:138:27: error: field has incomplete type 'struct re_pattern_buffer'
struct re_pattern_buffer pat_buff;
^
../gateAs.h:138:9: note: forward declaration of 're_pattern_buffer'
struct re_pattern_buffer pat_buff;
^
../gateAs.h:139:22: error: field has incomplete type 'struct re_registers'
struct re_registers regs;
^
../gateAs.h:139:9: note: forward declaration of 're_registers'
struct re_registers regs;
^
2 errors generated.
make[2]: *** [gatePv.o] Error 1
make[1]: *** [install.darwin-x86] Error 2
make: *** [src.install] Error 2
mac-130048:gateway2_0_6_0 odell$

I get the same error message with more recent versions of ca-gateway as well. I'm using EPICS 3.15.7.
This version of gateway compiles fine on the beagle bone. Is there an obvious fix for this?

[ralphlange]

This seems related to the Regular Expression library.

[vodellv]

great! Is there an obvious fix I can make? I'm at a loss as to what to do... what is the Regular Expression library?

[ralphlange]

Had I ever used a Mac in my life... I might even know.
Sorry. Maybe ask on tech-talk. There are always a dozen or two Mac users reading.

[vodellv]

ok, where is tech-talk?

[ralphlange]

https://epics.anl.gov/tech-talk/index.php

[anjohnson]

Evidently Apple's version of regex.h doesn't have the same definitions in it that glibc's does on Linux. Switching to the gateway to build against PCRE worked for me on Mojave.

[ralphlange]

Ok. When time permits, I will

• document this in the README
• add a MacOS job on Travis.

[ericonr]

re_* functions and structs are GNU specific, per https://www.gnu.org/software/gnulib/manual/html_node/GNU-Regex-Functions.html

They are available on glibc, of course, as well as gnulib.

I would expect the POSIX functions from <regex.h> to be more portable, and they seem to still support pattern buffers and registers. I don't know if anyone would be interested in doing the porting work, though, given that building with PCRE swiftly avoids this issue.

I came across this issue when building the gateway on a musl-based system, FWIW.

[ralphlange]

Given that basically everyone compiles the Gateway with PCRE support...

[ericonr]

Yeah, probably not worth the effort :)

I don't even intend to use it on musl, it was just included in a shared build definition used on Debian and Alpine.

That said, as a matter of curiosity, the gateway in use at LNLS/SIRIUS isn't built with PCRE.

[ralphlange]

That said, as a matter of curiosity, the gateway in use at LNLS/SIRIUS isn't built with PCRE.

Which would validate the rule, right?!

[anjohnson]

Which would validate the rule, right?!

Only if that were the only exception. The APS PV name patterns were all developed using the GNU regex, so switching to PCRE would require some work. We're running about 57 gateways at the moment, all on RHEL.

[ralphlange]

Meh.

How do you manage without negative lookahead?