Well, I haven't run into it w/ CW yet (haven't really gotten into writing for the Pilot yet), but based on my Microsoft experience, precompiled headers are a Bad Thing (tm). In the subject under discussion, where someone wanted to disable the floating point traps, he defined the symbol #define _DONT_USE_FP_TRAPS_ 1 Now, somewhere in the .h files there is presumably a conditional like #if _DONT_USE_FP_TRAPS_ /* fp routine prototypes */ #else /* fp trap prototypes */ #endif But if you are using precompiled headers, you don't actually refer to the .h files, you refer to a pre-digested version that presumably has symbol tables & such already pre-built based on the headers (I don't really know what goes into precompiled header databases, but symbol tables seems like a good guess). The problem with this is that if the pre-digested version was created with different conditionals, you'll never see the effect you're after unless you somehow force it to regenerate the precompiled header database. The compiler is supposed to be smart enough to recognize when something that requires this to be done has changed, but the key phrase in that sentance is "supposed to be". In my experience they never are, causing endless hours of trying to track down nonexistant bugs in your code when the real bug is just that the conditionals you have set up are not being honored by the compiler. My advice: never use precompiled headers. Compilation times may be marginally longer, but you'll know what you're getting. -- -Richard M. Hartman [EMAIL PROTECTED] 186,000 mi./sec ... not just a good idea, it's the LAW! > -----Original Message----- > From: Michael S. Davis [mailto:[EMAIL PROTECTED]] > Sent: Wednesday, March 24, 1999 7:02 AM > To: [EMAIL PROTECTED] > Subject: GCC: Couple of Generic questions > > > > It just occurred to me that I do not have a pilot.h > header included in my program. But it compiles just > fine. > > When is it necessary? > > Also, how important or rather what is the purpose > of PILOT_PRECOMPILED_HEADERS_OFF. I know that it > controls using precompiled headers (duh!). But > what are the implications if one does or does not > use this? I don't, yet. Should I use it? > > > > ---------------------------------------------------- > Shoot-to-Win > > Protect the 2nd Amendment > ---------------------------------------------------- > >
