Error #2135: Compilation of class XXXX has no member (HP-UX IA64 ACC)

Error #2135: Compilation of class XXXX has no member:
"Hbstat. cpp", line 180: Error #2135: Class "diameter: sdiameterrootdef" has no
Member "_ MSG"
Pmsgdict = & prootdef-> MSG ;
^
However, the structure of sdiameterrootdef is as follows:
Struct sdiameterrootdef
{
Tuint32 version;
Tuint32 unused;
Sdiameterprotodict proto;
Sdiametervendordict vendor;
Sdiametertypedict type;
Sdiameteravpdict AVP;
Sdiametermsgdict MSG;
Sdiametermsgtempdict temp;
Sdiameterservicegroup service;
};
Obviously, MSG is a member variable, but the compiler prompts that there is no member "_ MSG", which is a bit strange...

By asking experts, we recommend that you use pre-compilation to see what it looks like. Then we bring the-E Option to compile, acc...-e hbstat. cpp
This line is foundCodePmsgdict = & prootdef-> MSG;
Pre-edited into pmsgdict = & prootdef->__ MSG ;//!?
So I suspect there is a macro definition like: # define MSG _ msg
Add the following code to solve the problem:
# Ifdef msg
# UNDEF msg
# Endif

However, you still need to find somewhere similar to # define MSG _ MSG to avoid type issues in the future.

Supplement:

The following definitions are found after verification:

/Usr/include/sys/msg. h

# Ifdef _ include_hpux_source
# Define MSG _ MSG/* keep xopen name-space clean */

The system header file is defined, and conflicts with the system header file memory ....