C Programming Language :: Line break in preprocessor output


	Line break in preprocessor output Hi Group- I want to use the C preprocessor to generate expanded text as a text processor for software test script generation. The preprocessor output will never be compiled. I need to insert newlines in the preprocessed output file but I can't figure out how to do it. Here's a stab at what I'm trying to do but failing: #define CMD(s) text s \ enter \ sleep 500 CMD(mmem:mdir "a1") CMD(mmem:mdir "a2") I'd like to output a literal newline for every macro line continuation character ('\'). I know my example won't work but it's the closest I've been able to get to actually get the output that I'd like to get, which is: text mmem:mdir "a1" enter sleep 500 text mmem:mdir "a2" enter sleep 500 What I get instead is: text mmem:mdir "a1" enter sleep 500 text mmem:mdir "a2" enter sleep 500 The desired newlines are missing. Does anyone know how to get the C proeprocessor to output a literal newline using macros? Thanks, John. "John Speth" <johnsp@yahoo.com> writes: > Does anyone know how to get the C proeprocessor to output a literal newline > using macros? I don't think that there is a way to do it. You might consider designating a character sequence to represent a new-line character and then postprocess the C preprocessor's output with another program that can replace that sequence with a new-line. -- int main(void){char p[]="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz.\ \n",q="kl BIcNBFr.NKEzjwCIxNJC";int i=sizeof p/2;char strchr();int putchar(\ );while(q){i+=strchr(p,q++)-p;if(i>=(int)sizeof p)i-=sizeof p-1;putchar(p[i]\ );}return 0;} On May 29, 5:23 pm, "John Speth" <johnsp@yahoo.com> wrote: - Hide quoted text - > Hi Group- > I want to use the C preprocessor to generate expanded text as a text > processor for software test script generation. The preprocessor output will > never be compiled. I need to insert newlines in the preprocessed output > file but I can't figure out how to do it. > Here's a stab at what I'm trying to do but failing: > #define CMD(s) text s \ > enter \ > sleep 500 > CMD(mmem:mdir "a1") > CMD(mmem:mdir "a2") > I'd like to output a literal newline for every macro line continuation > character ('\'). I know my example won't work but it's the closest I've > been able to get to actually get the output that I'd like to get, which is: > text mmem:mdir "a1" > enter > sleep 500 > text mmem:mdir "a2" > enter > sleep 500 > What I get instead is: > text mmem:mdir "a1" enter sleep 500 > text mmem:mdir "a2" enter sleep 500 > The desired newlines are missing. > Does anyone know how to get the C proeprocessor to output a literal newline > using macros? > Thanks, John. With some preprocessors, it's possible that the sequence of characters \u000A will expand into a newline during preprocessing (this is almost legal C99 syntax, but the standard specifically says that this sort of thing isn't allowed (6.4.3:2 in N1124.pdf)). (I haven't tested, but it seems reasonable that at least one preprocessor will get confused into emitting a newline in this situation; the #defines would be substituted in stage 4, before the universal character names are even considered by the compiler.) One point of interest is that universal character names are one C99 feature that I've actually used in practice. -- ais523 John Speth wrote: > Hi Group- > I want to use the C preprocessor to generate expanded text as a text > processor for software test script generation. The preprocessor output will > never be compiled. I need to insert newlines in the preprocessed output > file but I can't figure out how to do it. The C preprocessor is probably the wrong tool. You might look into a program designed as a stand-alone macro language, like the old, I know, but trusty M4. On 29 May 2007, "John Speth" <johnsp@yahoo.com> wrote: > I want to use the C preprocessor to generate expanded text as a > text processor for software test script generation. The > preprocessor output will never be compiled. I need to insert > newlines in the preprocessed output file but I can't figure out > how to do it. Like others who have responded, I don't think there's a way to do this portably with the C preprocessor. But could you explain why you chose that particular tool? Why not use a "real" macro processor like m4? http://en.wikipedia.org/wiki/M4_(computer_language) Since it's usually written in C, you should be able to build it for just about any platform. Dave -- D.a.v.i.d T.i.k.t.i.n t.i.k.t.i.n [at] a.d.v.a.n.c.e.d.r.e.l.a.y [dot] c.o.m "David Tiktin" <dtik@nospam.totally-bogus.com> wrote in message news:Xns993F77B3CA75Adtiktinnospambogusco@216.196.97.136... - Hide quoted text - > On 29 May 2007, "John Speth" <johnsp@yahoo.com> wrote: >> I want to use the C preprocessor to generate expanded text as a >> text processor for software test script generation. The >> preprocessor output will never be compiled. I need to insert >> newlines in the preprocessed output file but I can't figure out >> how to do it. > Like others who have responded, I don't think there's a way to do this > portably with the C preprocessor. But could you explain why you chose > that particular tool? Why not use a "real" macro processor like m4? > http://en.wikipedia.org/wiki/M4_(computer_language) > Since it's usually written in C, you should be able to build it for > just about any platform. (I'm the OP) I chose the C preprocessor because it seemed like a capable tool for the job AND it was at my fingertips. I'm looking for instant gratification. M4 looks like it'll work but now I have to spend an hour or two learning it. It appears simply outputting a newline is just plain not possible using the C proeprocessor. It's such a simple thing too :( Thanks to everyone for your help and suggestions. JJS