The C89 requirement is a wall that is hit by many software projects (PROJ.4, GDAL, MapServer/MapCache?) as many different compilers support different standards.

MapServer/MapCache? recently added the -Werror=declaration-after-statement to avoid compiler errors when variables are not declared at the beginning of the block: ​https://github.com/mapserver/mapcache/commit/219e54b45e4730b91111a6874e435a8ca8a1aa6d

Even Rouault recently mentioned that PROJ.4 also uses that flag, which is based on the GDAL use of it also: ​https://github.com/OSGeo/proj.4/blob/master/m4/ax_cflags_warn_all.m4#L35

Here are more ZOO-Project compile errors on Windows:

d:\build\mapserver-buildkit-2012\zoo-project-svn-20170731\zoo-project\zoo-kernel\service.h(273) : error C2061: syntax error : identifier 'hasKey'
d:\build\mapserver-buildkit-2012\zoo-project-svn-20170731\zoo-project\zoo-kernel\service.h(273) : error C2059: syntax error : ';'
d:\build\mapserver-buildkit-2012\zoo-project-svn-20170731\zoo-project\zoo-kernel\service.h(273) : error C2059: syntax error : 'type'
d:\build\mapserver-buildkit-2012\zoo-project-svn-20170731\zoo-project\zoo-kernel\service.h(285) : error C2061: syntax error : identifier 'hasElement'
d:\build\mapserver-buildkit-2012\zoo-project-svn-20170731\zoo-project\zoo-kernel\service.h(285) : error C2059: syntax error : ';'
d:\build\mapserver-buildkit-2012\zoo-project-svn-20170731\zoo-project\zoo-kernel\service.h(285) : error C2059: syntax error : 'type'
d:\build\mapserver-buildkit-2012\zoo-project-svn-20170731\zoo-project\zoo-kernel\service.h(297) : error C2061: syntax error : identifier 'contains'
d:\build\mapserver-buildkit-2012\zoo-project-svn-20170731\zoo-project\zoo-kernel\service.h(297) : error C2059: syntax error : ';'
d:\build\mapserver-buildkit-2012\zoo-project-svn-20170731\zoo-project\zoo-kernel\service.h(297) : error C2059: syntax error : 'type'
d:\build\mapserver-buildkit-2012\zoo-project-svn-20170731\zoo-project\zoo-kernel\service.h(316) : error C2061: syntax error : identifier 'addServiceToRegistry'
d:\build\mapserver-buildkit-2012\zoo-project-svn-20170731\zoo-project\zoo-kernel\service.h(316) : error C2059: syntax error : ';'
d:\build\mapserver-buildkit-2012\zoo-project-svn-20170731\zoo-project\zoo-kernel\service.h(316) : error C2059: syntax error : 'type'
d:\build\mapserver-buildkit-2012\zoo-project-svn-20170731\zoo-project\zoo-kernel\service.h(328) : warning C4273: '_snprintf' : inconsistent dll linkage
        C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\INCLUDE\stdio.h(349) : see previous definition of '_snprintf'
ulinet.c(92) : error C2143: syntax error : missing ';' before 'type'
ulinet.c(93) : error C2275: '_HINTERNET' : illegal use of this type as an expression
        d:\build\mapserver-buildkit-2012\zoo-project-svn-20170731\zoo-project\zoo-kernel\ulinet.h(87) : see declaration of '_HINTERNET'
ulinet.c(93) : error C2065: 'psInternet' : undeclared identifier
ulinet.c(94) : error C2065: 'psInternet' : undeclared identifier
ulinet.c(94) : warning C4047: '!=' : 'int' differs in levels of indirection from 'void *'
ulinet.c(95) : error C2065: 'psInternet' : undeclared identifier
ulinet.c(95) : error C2223: left of '->cookie' must point to struct/union
ulinet.c(96) : error C2065: 'psInternet' : undeclared identifier
ulinet.c(96) : error C2223: left of '->cookie' must point to struct/union
ulinet.c(246) : warning C4013: 'strtok_r' undefined; assuming extern returning int
ulinet.c(246) : warning C4047: '=' : 'char *' differs in levels of indirection from 'int'
ulinet.c(247) : error C2143: syntax error : missing ';' before 'type'
ulinet.c(248) : error C2143: syntax error : missing ';' before 'type'
ulinet.c(249) : error C2065: 'cnt' : undeclared identifier
ulinet.c(251) : error C2065: 'cnt' : undeclared identifier
ulinet.c(254) : error C2065: 'cnt' : undeclared identifier
ulinet.c(258) : warning C4047: '=' : 'char *' differs in levels of indirection from 'int'
ulinet.c(259) : error C2065: 'cnt' : undeclared identifier
ulinet.c(281) : warning C4047: '=' : 'char *' differs in levels of indirection from 'int'
ulinet.c(282) : error C2143: syntax error : missing ';' before 'type'
ulinet.c(283) : error C2065: 'i' : undeclared identifier
ulinet.c(284) : error C2065: 'i' : undeclared identifier
ulinet.c(289) : error C2143: syntax error : missing ';' before 'type'
ulinet.c(290) : error C2065: 'j' : undeclared identifier
ulinet.c(291) : error C2065: 'j' : undeclared identifier
ulinet.c(292) : error C2065: 'j' : undeclared identifier
ulinet.c(292) : error C2065: 'i' : undeclared identifier
ulinet.c(294) : error C2065: 'j' : undeclared identifier
ulinet.c(295) : error C2065: 'j' : undeclared identifier
ulinet.c(298) : error C2275: 'map' : illegal use of this type as an expression
        d:\build\mapserver-buildkit-2012\zoo-project-svn-20170731\zoo-project\zoo-kernel\service.h(191) : see declaration of 'map'
ulinet.c(298) : error C2065: 'tmpMap' : undeclared identifier
ulinet.c(299) : error C2065: 'tmpMap' : undeclared identifier
ulinet.c(299) : warning C4047: '!=' : 'int' differs in levels of indirection from 'void *'
ulinet.c(300) : error C2065: 'i' : undeclared identifier
ulinet.c(300) : error C2065: 'tmpMap' : undeclared identifier
ulinet.c(300) : error C2223: left of '->value' must point to struct/union
ulinet.c(300) : error C2198: 'AddMissingHeaderEntry' : too few arguments for call
ulinet.c(302) : error C2065: 'i' : undeclared identifier
ulinet.c(303) : error C2065: 'i' : undeclared identifier
ulinet.c(305) : warning C4047: '=' : 'char *' differs in levels of indirection from 'int'
ulinet.c(539) : warning C4018: '<' : signed/unsigned mismatch
NMAKE : fatal error U1077: '"C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\BIN\cl.EXE"' : return code '0x2'
Stop.

zoo-project svn 229 Ubuntu 11.04 x86_64 with kernel 2.6.38-8 (up-to-date stable patches on ticket submission date) Python 2.7.1+ (r271:86832) from Ubuntu packages

Attached is the zcfg. When foo.py contains:

def Foo(conf,inputs,outputs):

outputsResult?value?=inputsa?value? return 3

everything works fine. When adding: input json to the beginning of the file, zoo returns a SEGFAULT exception. JSON module works fine in standalone python. Execution tested with:

./zoo_loader.cgi "request=execute&service=WPS&version=1&identifier=Foo&DataInputs?=a=foo"

The following lines in the function printFullDescription (service_internal.c) causes a segmentation fault in some situations, namely if the pointer e->supported is NULL (tested on Windows 7):

if(_tmp0==NULL){
   xmlAddChild(nc6,nc8);
   _tmp0=e->supported;
   if(getMap(_tmp0->content,"range")!=NULL ||
      getMap(_tmp0->content,"rangeMin")!=NULL ||
      getMap(_tmp0->content,"rangeMax")!=NULL ||
      getMap(_tmp0->content,"rangeClosure")!=NULL ) { 
      tmp1=_tmp0->content;
      goto doRange;
   }
}