lftp 4.7.2 build fails in Cygwin

lftp 4.7.2 build fails in Cygwin

[Andrew Schulman]

Cygwin 2.5.1 x86_64
g++ 5.3.0

In Cygwin, build of lftp 4.7.2 fails in two places:

(1)

/home/andrex/dev/cygwin/lftp/lftp-4.7.2-1.x86_64/src/lftp-4.7.2/src/xmalloc.h:31:38:
error: expected ';', ',' or ')' before '=' token
 char *xstrdup(const char *s,int spare=0);
                                      ^

g++ seems not to like the default value 'spare=0' in the function declaration.
The function definition (in xmalloc.cc) doesn't include the default value:

char *xstrdup(const char *s,int spare)
{
   if(!s)
      return (char*)xmalloc(spare);
#ifdef MEM_DEBUG
   printf("xstrdup \"%s\"\n",s);
#endif
   size_t len=strlen(s)+1;
   char *mem=(char*)xmalloc(len+spare);
   memcpy(mem,s,len);
   return mem;
}

I tried removing the default value from the declaration in xmalloc.h, or adding
it into the definition in xmalloc.cc.  But the build still failed either way.

Finally I just removed the 'spare' parameter from the function, since a look
through the source code shows that it's never used.  The patch for that is
below.  

But I don't know why Cygwin's g++ (5.3.0) chokes on this. The same construction
was present in 4.6.5, which compiled fine in Cygwin.

(2)

/home/andrex/dev/cygwin/lftp/lftp-4.7.2-1.x86_64/src/lftp-4.7.2/src/xmalloc.h:32:21:
error: expected ';', ',' or ')' before '&' token
 char *xstrset(char *&mem,const char *s);
                     ^
/home/andrex/dev/cygwin/lftp/lftp-4.7.2-1.x86_64/src/lftp-4.7.2/src/xmalloc.h:33:21:
error: expected ';', ',' or ')' before '&' token
 char *xstrset(char *&mem,const char *s,size_t n);
                     ^

Here g++ doesn't like *&mem. Again I don't know why g++ chokes on this, since
the same construction was present in 4.6.5, which compiled fine in Cygwin.

Does anyone know the right solution for these problems? Some compiler switches
I'm missing?

Thanks,
Andrew

===

diff -urN lftp-4.7.1.orig/src/xmalloc.cc lftp-4.7.1/src/xmalloc.cc
--- lftp-4.7.1.orig/src/xmalloc.cc  2015-11-25 05:27:17.000000000 -0500
+++ lftp-4.7.1/src/xmalloc.cc   2016-05-03 18:09:15.709557300 -0400
@@ -83,15 +83,15 @@
    free(p);
 }

-char *xstrdup(const char *s,int spare)
+char *xstrdup(const char *s)
 {
    if(!s)
-      return (char*)xmalloc(spare);
+     return 0;
 #ifdef MEM_DEBUG
    printf("xstrdup \"%s\"\n",s);
 #endif
    size_t len=strlen(s)+1;
-   char *mem=(char*)xmalloc(len+spare);
+   char *mem=(char*)xmalloc(len);
    memcpy(mem,s,len);
    return mem;
 }
diff -urN lftp-4.7.1.orig/src/xmalloc.h lftp-4.7.1/src/xmalloc.h
--- lftp-4.7.1.orig/src/xmalloc.h   2015-11-25 05:27:18.000000000 -0500
+++ lftp-4.7.1/src/xmalloc.h    2016-05-03 18:06:28.969612500 -0400
@@ -28,7 +28,7 @@

 void *xmalloc(size_t);
 void *xrealloc(void *,size_t);
-char *xstrdup(const char *s,int spare=0);
+char *xstrdup(const char *s);
 char *xstrset(char *&mem,const char *s);
 char *xstrset(char *&mem,const char *s,size_t n);
 #define alloca_strdup(s) alloca_strdup2((s),0)


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Re: lftp 4.7.2 build fails in Cygwin

[Hans-Bernhard Bröker]

Am 26.05.2016 um 19:20 schrieb Andrew Schulman:
> Cygwin 2.5.1 x86_64
> g++ 5.3.0
>
> In Cygwin, build of lftp 4.7.2 fails in two places:
>
> (1)
>
> /home/andrex/dev/cygwin/lftp/lftp-4.7.2-1.x86_64/src/lftp-4.7.2/src/xmalloc.h:31:38:
> error: expected ';', ',' or ')' before '=' token
>  char *xstrdup(const char *s,int spare=0);
>                                       ^
>
> g++ seems not to like the default value 'spare=0' in the function declaration.

I'm convinced g++ actually likes that just fine.  The problem is that 
this header is being pulled in by a plain C source file: lftp_rl.c.  But 
C does no have default arguments; those only exist in C++.

The underlying reason appearst to be that there is a conflict between 
src/History.h and /usr/include/readline/history.h.

This file wants to include readline's history.h, but "thanks" to 
Windows's harebrained handling of filename cases, gets src/History.h 
instead.  Which is a C++ header file, and new with 4.7.2.

> (2)
>
> /home/andrex/dev/cygwin/lftp/lftp-4.7.2-1.x86_64/src/lftp-4.7.2/src/xmalloc.h:32:21:
> error: expected ';', ',' or ')' before '&' token
>  char *xstrset(char *&mem,const char *s);

Same problem, same cause: that is not legal C code, so the C compiler is 
correct in rejecting it.

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Re: lftp 4.7.2 build fails in Cygwin

[Andrew Schulman]

> Am 26.05.2016 um 19:20 schrieb Andrew Schulman:
> > Cygwin 2.5.1 x86_64
> > g++ 5.3.0
> >
> > In Cygwin, build of lftp 4.7.2 fails in two places:
> >
> > (1)
> >
> > /home/andrex/dev/cygwin/lftp/lftp-4.7.2-1.x86_64/src/lftp-4.7.2/src/xmalloc.h:31:38:
> > error: expected ';', ',' or ')' before '=' token
> >  char *xstrdup(const char *s,int spare=0);
> >                                       ^
> >
> > g++ seems not to like the default value 'spare=0' in the function declaration.
> 
> I'm convinced g++ actually likes that just fine.  The problem is that 
> this header is being pulled in by a plain C source file: lftp_rl.c.  But 
> C does no have default arguments; those only exist in C++.
> 
> The underlying reason appearst to be that there is a conflict between 
> src/History.h and /usr/include/readline/history.h.
> 
> This file wants to include readline's history.h, but "thanks" to 
> Windows's harebrained handling of filename cases, gets src/History.h 
> instead.  Which is a C++ header file, and new with 4.7.2.

Thanks, Hans-Bernard! You nailed it. I wasn't close to figuring that out. The
patch below solves the problem.  Andrew

diff -urN lftp-4.7.2.orig/src/lftp_rl.c lftp-4.7.2/src/lftp_rl.c
--- lftp-4.7.2.orig/src/lftp_rl.c   2016-02-20 08:57:53.000000000 -0500
+++ lftp-4.7.2/src/lftp_rl.c    2016-05-27 05:23:06.893807600 -0400
@@ -20,7 +20,7 @@
 #include <config.h>
 #include <stdio.h>
 #include <readline.h>
-#include <history.h>
+#include <readline/history.h>
 #include <stdlib.h>
 #include <string.h>
 #include "lftp_rl.h"


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