Using %z in printf is not portable

[Dirk Zimoch]

Some code in EPICS uses printf with the z format modifier for size_t arguments, as in "%zu". This is not portable. VxWorks (at least up to version 6.9.0) does not understand this and prints "zu" and then shifts all the remaining arguments to the wrong format specifier!
Older Windows versions use "%Iu" for the same purpose.

Affected code:
modules/libcom/src/error/errlog.c (2x)
modules/libcom/test/epicsErrlogTest.c
modules/libcom/test/yajl_test.c (2x)
modules/pvAccess/pvtoolsSrc/pvlist.cpp (2x)
modules/pvAccess/src/ioc/reftrackioc.cpp (2x)
modules/pvAccess/src/remote/blockingUDPTransport.cpp (4x)
modules/pvAccess/src/remote/codec.cpp (2x)
modules/pvAccess/src/remote/transportRegistry.cpp
modules/pvAccess/src/server/responseHandlers.cpp
modules/pvAccess/testApp/remote/testChannelConnect.cpp
modules/pvAccess/testApp/remote/testmonitorfifo.cpp (4x)
modules/pvData/src/factory/FieldCreateFactory.cpp (2x)
modules/pvData/testApp/pv/performstruct.cpp (2x)
modules/pvData/testApp/pv/testPVData.cpp
modules/pva2pva/pdbApp/pdbgroup.cpp
modules/pva2pva/pdbApp/pvalink.cpp (3x)
modules/pva2pva/pdbApp/pvalink_jlif.cpp
modules/pva2pva/testApp/testpdb.cpp (2x)

[Dirk Zimoch (dirk.zimoch)]

I suggest to #define an osd macro to be used with the printf format string, like those in inttypes.h (which also does not support size_t).

[Ralph Lange (ralph-lange)]

The problem is that size_t has a different size (!) on different implementations.

The usual (only?) way to get this portable is to cast the argument to something like 'unsigned long long' and use the matching format specifier.

[rivers (rivers)]

This issue was discussed in a previous bug report.

https://bugs.launchpad.net/epics-base/+bug/1740426

[rivers (rivers)]

I believe %z is supported in Visual Studio 2015 and later. Have we said that older versions are no longer supported?

I have not tested %z on vxWorks 6.9.4.1, which is what we use at the APS, but I think Andrew would have noticed if it did not work? What is the minimum version of vxWorks currently supported?

[Dirk Zimoch (dirk.zimoch)]

Simple test on the vxWorks shell:
-> printf "%u %zu %u\n",1,2,3
1 zu 2

[rivers (rivers)]

That simple vxWorks shell test also fails on 6.9.4.1.