FSJTM@ALASKA.BITNET (...Ar Henchou Kuzh...) (10/20/88)
[]
Has anyone else run into this "feature" of Manx C?
It happens with both 3.4b and 3.6a (at least, the ones I have).
Minimal case -
char *array[] = { "s1" "s2" };
That's it.
Now, it seems obvious to me (and every other compiler I
have used) that this is a syntax error. But the Manx compiler never even
burps. What it does do is concat "s1" and "s2" into "s1s2" and put just the
one pointer into array. This one took me quite a while to find once when
I had a large array and forgot a few commas.
I've sent a note off to Manx (since long distance calls from here can
cost an arm and a leg), but from what I've been hearing on the net about their
support, I don't expect them to reply (at least, I'm not holding my breath).
Just thought I'd see if anyone else knew about this, and maybe save someone
a few hours of head-beating with a debugger.
[jtm]
John McCranie FSJTM@ALASKA
Box 900306
University of Alaska, Fairbanks 99775-1040
Hawk looks down from lofty flight Dzur stalks and blends with night.ali@polya.Stanford.EDU (Ali T. Ozer) (10/23/88)
In article <8810192323.AA21251@jade.berkeley.edu> <FSJTM%ALASKA.BITNET@jade.berkeley.edu> writes: >Has anyone else run into this "feature" of Manx C? >char *array[] = { "s1" "s2" }; >Now, it seems obvious to me (and every other compiler I >have used) that this is a syntax error. But the Manx compiler never even >burps. What it does do is concat "s1" and "s2" into "s1s2" ... That *is* a feature! ANSI C states that strings can be concatanated as in the above case. This lets you break long strings into multiple lines to make your source look prettier. Seems like Manx does the ANSI thing in this case (instead of giving you a syntax error). Ali Ozer
bader+@andrew.cmu.edu (Miles Bader) (10/23/88)
FSJTM@ALASKA.BITNET (...Ar Henchou Kuzh...) writes: > char *array[] = { "s1" "s2" }; > Now, it seems obvious to me (and every other compiler I > have used) that this is a syntax error. But the Manx compiler never even > burps. What it does do is concat "s1" and "s2" into "s1s2" and put just the In ANSI c, putting two string literals next to one another like that is supposed to be equivalent to a string literal that is the concatenation of the two. So manx is correct by that standard... -Miles
jyegiguere@lotus.waterloo.edu (Eric Giguere) (10/23/88)
In article <8810192323.AA21255@jade.berkeley.edu> <FSJTM%ALASKA.BITNET@jade.berkeley.edu> writes: >[] >Has anyone else run into this "feature" of Manx C? >It happens with both 3.4b and 3.6a (at least, the ones I have). >Minimal case - > >char *array[] = { "s1" "s2" }; > >That's it. >Now, it seems obvious to me (and every other compiler I >have used) that this is a syntax error. But the Manx compiler never even >burps. What it does do is concat "s1" and "s2" into "s1s2" and put just the >one pointer into array. This one took me quite a while to find once when >I had a large array and forgot a few commas. This isn't a bug... I imagine it's one step in Manx' upgrading to ANSI C. In ANSI C, two strings separated only by whitespace are automatically concatenated.... useful for long strings. -- --------------------------------------------------------------------------- Eric Giguere 268 Phillip St. #CL-46, Waterloo, Ont. N2L 6G9 jyegiguere@lotus.waterloo.edu (519) 746-0792 GIGUERE@WATCSG.BITNET "No, that's not how you pronounce it..."
toebes@sas.UUCP (John Toebes) (10/24/88)
In article <8810192323.AA21251@jade.berkeley.edu> <FSJTM%ALASKA.BITNET@jade.berkeley.edu> writes: >[] >Has anyone else run into this "feature" of Manx C? >It happens with both 3.4b and 3.6a (at least, the ones I have). >Minimal case - > >char *array[] = { "s1" "s2" }; > >That's it. >Now, it seems obvious to me (and every other compiler I >have used) that this is a syntax error. But the Manx compiler never even >burps. What it does do is concat "s1" and "s2" into "s1s2" and put just the >one pointer into array. The automatic concatenation of strings is a feature that has been introduced by the ANSI comittee. It is actually quite useful when you want to do something like: #define CSI "\x9B" #define EEOL CSI "K" printf(EEOL "This is a string" ); With the ANSI standard recently voted out, expect to see more compilers performing this type of operation, not less. /*---------------------All standard Disclaimers apply---------------------*/ /*----Working for but not officially representing SAS or Lattice Inc.-----*/ /*----John A. Toebes, VIII usenet:...!mcnc!rti!sas!toebes-----*/ /*------------------------------------------------------------------------*/
mrr@amanpt1.zone1.com (Mark Rinfret) (10/24/88)
In article <8810192323.AA21251@jade.berkeley.edu>, FSJTM@ALASKA.BITNET (...Ar Henchou Kuzh...) writes: > [] > Has anyone else run into this "feature" of Manx C? > It happens with both 3.4b and 3.6a (at least, the ones I have). > Minimal case - > > char *array[] = { "s1" "s2" }; > > That's it. > Now, it seems obvious to me (and every other compiler I > have used) that this is a syntax error. But the Manx compiler never even > burps. What it does do is concat "s1" and "s2" into "s1s2" and put just the > one pointer into array. Believe it or not, this is a FEATURE, not a bug. Look in paragraph 3.7 of the "Compiler" section of your reference manual. The heading is "String merging" - what the compiler does when it finds adjacent character strings. I suppose this is useful for defining long strings which don't fit on one line. The example in the book illustrates the construction of a string containing preprocessor defined symbols. Mark -- < Mark R. Rinfret, mrr@amanpt1.ZONE1.COM | ...rayssd!galaxia!amanpt1!mrr > < HyperView Systems Corp. Home: 401-846-7639 > < 28 Jacome Way Work: 401-849-9390 x301 > < Middletown, RI 02840 Hypermedia R Us! >
glennl@cit-vlsi.Caltech.Edu (Glenn M. Lewis) (10/24/88)
In article <8810192323.AA21251@jade.berkeley.edu> <FSJTM%ALASKA.BITNET@jade.berkeley.edu> writes: |[] |Has anyone else run into this "feature" of Manx C? |It happens with both 3.4b and 3.6a (at least, the ones I have). |Minimal case - |char *array[] = { "s1" "s2" }; |... What it does do is concat "s1" and "s2" into "s1s2" and put just the |one pointer into array... |Just thought I'd see if anyone else knew about this, and maybe save someone |a few hours of head-beating with a debugger... | John McCranie FSJTM@ALASKA On page cc.20 (in the Compiler section) of the Manx Aztec C manual, under section 3.7, it says: The compiler will merge adjacent character strings. For example, printf("file=" __FILE__ " line = %d func= " __FUNC__ , __LINE__ ); -- Glenn Lewis glennl@vlsi.caltech.edu
lapin@ihuxy.ATT.COM (Tweedle Dee & Tweedle Dum) (10/25/88)
In article <8810192323.AA21251@jade.berkeley.edu> <FSJTM%ALASKA.BITNET@jade.berkeley.edu> writes: >[] >Has anyone else run into this "feature" of Manx C? >It happens with both 3.4b and 3.6a (at least, the ones I have). >Minimal case - > >char *array[] = { "s1" "s2" }; > >That's it. >Now, it seems obvious to me (and every other compiler I >have used) that this is a syntax error. But the Manx compiler never even >burps. This is not an error. According to the proposed ANSI C standard, the two strings are concatentated, yielding "s1s2". The purpose of this is so that long text lines can still be readable. e.g. char *msg = "The quick brown fox jumped over the " "lazy brown dog."; My source of information: The C Programming Language 2nd Ed. (pg. 38) Kernigan/Ritchie Prentice Hall, 1988 David Roch ...!att!ihuxy!lapin or lapin@ihuxy.att.com