How to stop compilation when a header file is missing

[jacek.dziedzic]

Hi!

I have a program that #includes a header file of an external
library.
If the environment is set-up correctly, this file is found in the
include path
and everything works.

Now, assume that a user forgot to either install the external
library
or to add the relevant directory to the include path. Obviously, the
compiler complains about a missing .h file, but then spews out
several screenfuls of error messages, as it does not recognize symbols
brought in by the include file that's missing. By doing this, it
quickly
hides the real error from the user.

Is there any way to have the compiler stop after it notices the
header
file is missing, without mindlessly trying to parse the rest of the
file?
Before I'm sent off to RTFM of the compiler to find the relevant
switch
or pragma, is there a (quasi)-portable way of achieving this through
some clever source code wizardry, regardless of the compiler?
Maybe there's a well-known way to generate an absolutely fatal
compilation error in an #ifndef for a symbol brought in by the header
file that's missing? Is #error C++ or a g++ extension?

TIA,
- J.

[Victor Bazarov]

ja************@gmail.com wrote:

Hi!

I have a program that #includes a header file of an external
library.
If the environment is set-up correctly, this file is found in the
include path
and everything works.

Now, assume that a user forgot to either install the external
library
or to add the relevant directory to the include path. Obviously, the
compiler complains about a missing .h file, but then spews out
several screenfuls of error messages, as it does not recognize symbols
brought in by the include file that's missing. By doing this, it
quickly
hides the real error from the user.

So? It seems a user problem to deal with errors in the orderly
fashion, no?

>
Is there any way to have the compiler stop after it notices the
header
file is missing, without mindlessly trying to parse the rest of the
file?
Before I'm sent off to RTFM of the compiler to find the relevant
switch
or pragma, is there a (quasi)-portable way of achieving this through
some clever source code wizardry, regardless of the compiler?

No.

Maybe there's a well-known way to generate an absolutely fatal
compilation error in an #ifndef for a symbol brought in by the header
file that's missing? Is #error C++ or a g++ extension?

#error is C++. How does that help? Unless your installation is
going to replace some placeholder with the only directive in it...

V
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