Re: [dpdk-dev] [EXT] Re: [PATCH v4] doc: announce API changes for Windows compatibility

[Akhil Goyal <gakhil@marvell.com>]

> 21/07/2021 21:55, Dmitry Kozlyuk:
> > Windows headers define `s_addr`, `min`, and `max` as macros.
> > If DPDK headers are included after Windows ones, DPDK structure
> > definitions containing fields with these names get broken (example 1),
> > as well as any usage of such fields (example 2). If DPDK headers
> > undefined these macros, it could break consumer code (example 3).
> > It is proposed to rename structure fields in DPDK, because Win32 headers
> > are used more widely than DPDK, as a general-purpose platform compared
> > to domain-specific kit, and are harder to fix because of that.
> > Exact new names are left for further discussion.
> >
> > Example 1:
> >
> >     /* in DPDK public header included after windows.h */
> >     struct rte_type {
> >         int min;    /* ERROR: `min` is a macro */
> >     };
> >
> > Example 2:
> >
> >     #include <rte_ether.h>
> >     #include <winsock2.h>
> >     struct rte_ether_hdr eh;
> >     eh.s_addr.addr_bytes[0] = 0;    /* ERROR: `addr_s` is a macro */
> >
> > Example 3:
> >
> >     #include <winsock2.h>
> >     #include <rte_ether.h>
> >     struct in_addr addr;
> >     addr.s_addr = 0;      /* ERROR: there is no `s_addr` field,
> >                              and `s_addr` macro is undefined by DPDK. */
> >
> > Commit 6c068dbd9fea ("net: work around s_addr macro on Windows")
> > modified definition of `struct rte_ether_hdr` to avoid the issue.
> > However, the workaround assumes `#define s_addr S_addr.S_un`
> > in Windows headers, which is not a part of official API.
> > It also complicates the definition of `struct rte_ether_hdr`.
> >
> > Signed-off-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
> > Acked-by: Khoa To <khot@microsoft.com>
> > ---
> > +* net: ``s_addr`` and ``d_addr`` fields of ``rte_ether_hdr`` structure
> > +  will be renamed in DPDK 21.11 to avoid conflict with Windows Sockets
> headers.
> > +
> > +* compressdev: ``min`` and ``max`` fields of ``rte_param_log2_range``
> structure
> > +  will be renamed in DPDK 21.11 to avoid conflict with Windows Sockets
> headers.
> 
> The struct rte_param_log2_range should also be renamed to include
> "compress" prefix.
> But as we break the struct API, it is not an issue I guess.
> 
> > +* cryptodev: ``min`` and ``max`` fields of ``rte_crypto_param_range``
> structure
> > +  will be renamed in DPDK 21.11 to avoid conflict with Windows Sockets
> headers.
> 
> Acked-by: Thomas Monjalon <thomas@monjalon.net>
> 
Can we have a local variable named as min/max?
If not, then I believe it is not a good idea.