When trying to compile large (approx. 2.2mb) source file I'm getting
following error:

nbytes = 65600, ph_maxsize = 65520
Internal error: ph 1848
--- errorlevel 1

In c++ beta forum one said its due to macro expansion buffer overflow. Is there any way to tell dmc to use larger buffer or any other way around this problem?

did you set -HP in your dmc command line?
http://www.digitalmars.com/ctg/sc.html#dashCapHCapP

Michael wrote:
> When trying to compile large (approx. 2.2mb) source file I'm getting
> following error:
> 
> nbytes = 65600, ph_maxsize = 65520
> Internal error: ph 1848
> --- errorlevel 1
> 
> In c++ beta forum one said its due to macro expansion buffer
> overflow. Is there any way to tell dmc to use larger buffer or any
> other way around this problem?

== Quote from chris elliott (biol75@york.ac.uk)'s article
> did you set -HP in your dmc command line? http://www.digitalmars.com/ctg/sc.html#dashCapHCapP

Yes I tried values from 50 to 1000, same error though.

Michael wrote:
> When trying to compile large (approx. 2.2mb) source file I'm getting
> following error:
> 
> nbytes = 65600, ph_maxsize = 65520
> Internal error: ph 1848
> --- errorlevel 1
> 
> In c++ beta forum one said its due to macro expansion buffer
> overflow. Is there any way to tell dmc to use larger buffer or any
> other way around this problem?

This can happen also if you have an unterminated string, and the compiler tries to read in your whole source file into one string.

I'd try the 'divide-and-conquer' approach. Divide the source file in half, and see which side generates the error. Rinse, repeat.

This happens because of huge switch statement.
Huge means number of 'case' statements over 4050.
Smallest test case can be produced using following ruby script:
=== cut ===
print "int main() {\n"
print "\tint i = 0;\n"
print "\tswitch(i) {\n"

1.upto(ARGV[0].to_i) do |x|
	print "\tcase #{x}: goto dummy;\n";
end

print "\t}\n"
print "dummy:\n"
print "\treturn 0;\n"
print "}"
=== cut ===
Everything else in that huge file compiles fine. Anything can be done
about it?

Michael wrote:
> This happens because of huge switch statement.
> Huge means number of 'case' statements over 4050.
> Smallest test case can be produced using following ruby script:
> === cut ===
> print "int main() {\n"
> print "\tint i = 0;\n"
> print "\tswitch(i) {\n"
> 
> 1.upto(ARGV[0].to_i) do |x|
> 	print "\tcase #{x}: goto dummy;\n";
> end
> 
> print "\t}\n"
> print "dummy:\n"
> print "\treturn 0;\n"
> print "}"
> === cut ===
> Everything else in that huge file compiles fine. Anything can be done
> about it?

Try splitting the case statement into two:

switch (i)
{
   case 1:
   case 2:
     ...
   default:
   switch (i)
   {
    case 1000:
    case 1001:
    ...
   }
}

Hello,

Walter Bright wrote...
> > In c++ beta forum one said its due to macro expansion buffer overflow. Is there any way to tell dmc to use larger buffer or any other way around this problem?
> 
> This can happen also if you have an unterminated string, and the compiler tries to read in your whole source file into one string.

But only if the source is one long line. Otherwise the compiler will
give the error
   Lexical error: unterminated string


- Heinz

== Quote from Walter Bright (newshound1@digitalmars.com)'s article
> Michael wrote:
> > This happens because of huge switch statement.
> > Huge means number of 'case' statements over 4050.

What does the compiler do with case statements?  I was told as a
youth to use them instead of if elseif elseif ... else constructs
because they were more efficient.  Then I disassembled one (of my
old) compiler's output and saw that it just tested each case
sequentially; just like the if else construct.  On that (single)
basis, I've usually veered toward using arrays of functions
instead of case statements.  Instead of
switch( i )
{  case 0: do0thing;
   case 1: do1thing;
   case 2: do2thing;
}
I write:
do_n_thing[i]();

Is it customary nowadays in good compilers to transform switch statements into a set of internal jmps, or do they check thru every case sequentially?  How should one deal with 4000 cases?

David

DQNOK wrote:
> Is it customary nowadays in good compilers to transform switch
> statements into a set of internal jmps, or do they check thru
> every case sequentially?  How should one deal with 4000 cases?

Compilers use different strategies depending on the number and density of the cases.