Re: [screen-devel] [PATCH] Fix configure when CFLAGS="-Wall -Werror" is specified.

[Sadrul Habib Chowdhury]

* Giuseppe Scrivano had this to say on [13 Feb 2010, 22:44:04 +0100]:
> Hello,
> 
> this trivial patch fixes ./configure CFLAGS="-Wall -Werror".

Hi. Thanks for the patch!

It looks like when we configure with -Wall -Werror, even with your patch,
the configure gets some incorrect results, e.g. in my system, it fails to
find _exit, strftime, vsnprintf etc. It'd be good to catch those cases
too.

Also, I think it makes more sense to include the appropriate headers,
rather than declaring externs, e.g.:

        @@ -47,7 +47,15 @@ AC_PROG_GCC_TRADITIONAL
         AC_ISC_POSIX
         AC_USE_SYSTEM_EXTENSIONS

        -AC_TRY_RUN(main(){exit(0);},,[
        +AC_TRY_RUN([
        +#include <stdlib.h>
        +
        +int main()
        +{
        +  exit(0);
        +  return 0;
        +}
        +],,[
         if test $CC != cc ; then
         AC_NOTE(Your $CC failed - restarting with CC=cc)
         AC_NOTE()

instead of:

        @@ -47,7 +47,7 @@ AC_PROG_GCC_TRADITIONAL
         AC_ISC_POSIX
         AC_USE_SYSTEM_EXTENSIONS
         
        -AC_TRY_RUN(main(){exit(0);},,[
        +AC_TRY_RUN(extern void exit (int);int main(){exit(0);return 0;},,[
         if test $CC != cc ; then
         AC_NOTE(Your $CC failed - restarting with CC=cc)
         AC_NOTE()

Or, perhaps we should just make sure that we remove -Wall -Werror from
CFLAGS when running ./configure, to keep things simple?

Also, I am very interested in the patch attached at
https://savannah.gnu.org/bugs/?27318. However, I haven't had the time to
test it out. Some help on that would be really appreciated!

Cheers,
Sadrul


> Cheers,
> Giuseppe
> 
> >From 2323115d8b432eb85d5341da6664215ad75cda9a Mon Sep 17 00:00:00 2001
> From: Giuseppe Scrivano <address@hidden>
> Date: Sat, 13 Feb 2010 22:38:59 +0100
> Subject: [PATCH] Fix configure when CFLAGS="-Wall -Werror" is specified.
> 
> ---
>  src/configure.in |   68 ++++++++++++++++++++++++++++++++++++++++++-----------
>  1 files changed, 54 insertions(+), 14 deletions(-)
> 
> diff --git a/src/configure.in b/src/configure.in
> index 8c5762c..b1ed5d9 100644
> --- a/src/configure.in
> +++ b/src/configure.in
> @@ -47,7 +47,7 @@ AC_PROG_GCC_TRADITIONAL
>  AC_ISC_POSIX
>  AC_USE_SYSTEM_EXTENSIONS
>  
> -AC_TRY_RUN(main(){exit(0);},,[
> +AC_TRY_RUN(extern void exit (int);int main(){exit(0);return 0;},,[
>  if test $CC != cc ; then
>  AC_NOTE(Your $CC failed - restarting with CC=cc)
>  AC_NOTE()
> @@ -57,7 +57,7 @@ exec $0 $configure_args
>  fi
>  ])
>  
> -AC_TRY_RUN(main(){exit(0);},,
> +AC_TRY_RUN(extern void exit (int);int main(){exit(0); return 0;},,
>  exec 5>&2
>  eval $ac_link
>  AC_NOTE(CC=$CC; CFLAGS=$CFLAGS; LIBS=$LIBS;)
> @@ -289,11 +289,11 @@ dnl    ****  select()  ****
>  dnl
>  
>  AC_CHECKING(select)
> -AC_TRY_LINK(,[select(0, 0, 0, 0, 0);],, 
> -LIBS="$LIBS -lnet -lnsl"
> +AC_CHECK_FUNCS([select],,
> +[LIBS="$LIBS -lnet -lnsl"
>  AC_CHECKING(select with $LIBS)
> -AC_TRY_LINK(,[select(0, 0, 0, 0, 0);],, 
> -AC_MSG_ERROR(!!! no select - no screen))
> +AC_CHECK_FUNCS([select],,
> +AC_MSG_ERROR(!!! no select - no screen))]
>  )
>  dnl
>  dnl    ****  FIFO tests  ****
> @@ -320,7 +320,8 @@ AC_TRY_RUN([
>  #endif
>  
>  char *fin = "/tmp/conftest$$";
> -
> +extern void exit (int);
> +int
>  main()
>  {
>    struct stat stb;
> @@ -363,6 +364,7 @@ main()
>    if (select(1, &f, 0, 0, 0) == -1)
>      exit(1);
>    exit(0);
> +  return 0;
>  }
>  ], AC_NOTE(- your fifos are usable) fifo=1,
>  AC_NOTE(- your fifos are not usable))
> @@ -388,9 +390,10 @@ AC_TRY_RUN([
>  #ifndef S_IFIFO
>  #define S_IFIFO 0010000
>  #endif
> -
> +extern void exit (int);
>  char *fin = "/tmp/conftest$$";
>  
> +int
>  main()
>  {
>    struct timeval tv;
> @@ -411,6 +414,7 @@ main()
>    if (select(1, &f, 0, 0, &tv))
>      exit(1);
>    exit(0);
> +  return 0;
>  }
>  ], AC_NOTE(- your implementation is ok), 
>  AC_NOTE(- you have a broken implementation) AC_DEFINE(BROKEN_PIPE) fifobr=1)
> @@ -438,8 +442,11 @@ AC_TRY_RUN([
>  #include <sys/socket.h>
>  #include <sys/un.h>
>  
> +extern void exit (int);
> +
>  char *son = "/tmp/conftest$$";
>  
> +int
>  main()
>  {
>    int s1, s2, l;
> @@ -473,6 +480,7 @@ main()
>    if (select(1, &f, 0, 0, 0) == -1)
>      exit(1);
>    exit(0);
> +  return 0;
>  }
>  ], AC_NOTE(- your sockets are usable) sock=1,
>  AC_NOTE(- your sockets are not usable))
> @@ -493,8 +501,11 @@ AC_TRY_RUN([
>  #include <sys/socket.h>
>  #include <sys/un.h>
>  
> +extern void exit (int);
> +
>  char *son = "/tmp/conftest$$";
>  
> +int
>  main()
>  {
>    int s;
> @@ -511,6 +522,7 @@ main()
>      exit(1);
>    close(s);
>    exit(0);
> +  return 0;
>  }
>  ],AC_NOTE(- you are normal),
>  AC_NOTE(- unix domain sockets are not kept in the filesystem)
> @@ -561,6 +573,8 @@ AC_TRY_RUN([
>  
>  char *nam = "/tmp/conftest$$";
>  
> +extern void exit (int);
> +
>  #ifdef NAMEDPIPE
>  
>  #ifndef O_NONBLOCK
> @@ -570,7 +584,10 @@ char *nam = "/tmp/conftest$$";
>  #define S_IFIFO 0010000
>  #endif
>  
> +extern void exit (int);
> +
>  
> +int
>  main()
>  {
>    fd_set f;
> @@ -639,6 +656,7 @@ main()
>    if (select(1, &f, &f, 0, 0) != 2)
>      exit(1);
>    exit(0);
> +  return 0;
>  }
>  ],AC_NOTE(- select is ok),
>  AC_NOTE(- select can't count) AC_DEFINE(SELECT_BROKEN))
> @@ -655,27 +673,31 @@ AC_TRY_LINK(,[
>  #ifdef __hpux
>  __sorry_hpux_libcurses_is_totally_broken_in_10_10();
>  #else
> +extern void tgetent (char*, char*);
>  tgetent((char *)0, (char *)0);
>  #endif
>  ],,
>  LIBS="-ltermcap $olibs"
>  AC_CHECKING(libtermcap)
> -AC_TRY_LINK(,tgetent((char *)0, (char *)0);,,
> +AC_TRY_LINK(,extern void tgetent (char*, char*); tgetent((char *)0, (char 
> *)0);,,
>  LIBS="-ltermlib $olibs"
>  AC_CHECKING(libtermlib)
> -AC_TRY_LINK(,tgetent((char *)0, (char *)0);,,
> +AC_TRY_LINK(,extern void tgetent (char*, char*); tgetent((char *)0, (char 
> *)0);,,
>  LIBS="-lncursesw $olibs"
>  AC_CHECKING(libncursesw)
> -AC_TRY_LINK(,tgetent((char *)0, (char *)0);,,
> +AC_TRY_LINK(,extern void tgetent (char*, char*); tgetent((char *)0, (char 
> *)0);,,
>  LIBS="-lncurses $olibs"
>  AC_CHECKING(libncurses)
> -AC_TRY_LINK(,tgetent((char *)0, (char *)0);,,
> +AC_TRY_LINK(,extern void tgetent (char*, char*); tgetent((char *)0, (char 
> *)0);,,
>  AC_MSG_ERROR(!!! no tgetent - no screen)))))))
>  
>  AC_TRY_RUN([
> +extern void exit (int);
> +int
>  main()
>  {
> - exit(strcmp(tgoto("%p1%d", 0, 1), "1") ? 0 : 1);
> +  exit(strcmp(tgoto("%p1%d", 0, 1), "1") ? 0 : 1);
> +  return 0;
>  }], AC_NOTE(- you use the termcap database),
>  AC_NOTE(- you use the terminfo database) AC_DEFINE(TERMINFO))
>  AC_CHECKING(ospeed)
> @@ -745,6 +767,9 @@ AC_TRY_RUN([
>  #include <sys/types.h>
>  #include <sys/stat.h>
>  #include <stdio.h>
> +extern void exit (int);
> +
> +int
>  main()
>  {
>    struct stat sb;
> @@ -768,6 +793,7 @@ main()
>    fprintf(fp, "%d\n", sb.st_gid);
>    fclose(fp);
>    exit(0);
> +  return 0;
>  }
>  ],[
>      if test -f conftest_grp; then
> @@ -940,6 +966,9 @@ $nlist64
>  
>  struct nlist nl[2];
>  
> +extern void exit (int);
> +
> +int
>  main()
>  {
>  #if !defined(_AUX_SOURCE) && !defined(AUX)
> @@ -955,6 +984,7 @@ main()
>    if (nl[0].n_value == 0)
>      exit(1);
>    exit(0);
> +  return 0;
>  }
>    ],avensym=$av;break)
>    if test "$av" = _Loadavg; then
> @@ -1077,6 +1107,7 @@ hand()
>    got++;
>  }
>  
> +int
>  main()
>  {
>    /* on hpux we use sigvec to get bsd signals */
> @@ -1088,6 +1119,7 @@ main()
>      exit(1);
>  #endif
>    exit(0);
> +  return 0;
>  }
>  ],,AC_DEFINE(SYSVSIGS))
>  
> @@ -1158,6 +1190,9 @@ AC_TRY_LINK([#include <stdlib.h>], [fdwalk(NULL, 
> NULL);],AC_DEFINE(HAVE_FDWALK))
>  
>  AC_CHECKING(whether memcpy/memmove/bcopy handles overlapping arguments)
>  AC_TRY_RUN([
> +extern void exit (int);
> +
> +int
>  main() {
>    char buf[10];
>    strcpy(buf, "abcdefghi");
> @@ -1169,10 +1204,12 @@ main() {
>    if (strncmp(buf, "cdedef", 6))
>      exit(1);
>    exit(0); /* libc version works properly.  */
> +  return 0;
>  }], AC_DEFINE(USEBCOPY))
>  
>  AC_TRY_RUN([
>  #define bcopy(s,d,l) memmove(d,s,l)
> +int
>  main() {
>    char buf[10];
>    strcpy(buf, "abcdefghi");
> @@ -1184,11 +1221,13 @@ main() {
>    if (strncmp(buf, "cdedef", 6))
>      exit(1);
>    exit(0); /* libc version works properly.  */
> +  return 0;
>  }], AC_DEFINE(USEMEMMOVE))
>  
>  
>  AC_TRY_RUN([
>  #define bcopy(s,d,l) memcpy(d,s,l)
> +int
>  main() {
>    char buf[10];
>    strcpy(buf, "abcdefghi");
> @@ -1200,6 +1239,7 @@ main() {
>    if (strncmp(buf, "cdedef", 6))
>      exit(1);
>    exit(0); /* libc version works properly.  */
> +  return 0;
>  }], AC_DEFINE(USEMEMCPY))
>  
>  AC_SYS_LONG_FILE_NAMES
> @@ -1286,7 +1326,7 @@ fi
>  dnl Ptx bug workaround -- insert -lc after -ltermcap
>  test -n "$seqptx" && LIBS="-ltermcap -lc -lsocket -linet -lnsl -lsec -lseq"
>  
> -AC_TRY_RUN(main(){exit(0);},,AC_MSG_ERROR(Can't run the compiler - internal 
> error. Sorry.))
> +AC_TRY_RUN(extern void exit (int);int main(){exit(0); return 
> 0;},,AC_MSG_ERROR(Can't run the compiler - internal error. Sorry.))
>  
>  AC_OUTPUT(Makefile doc/Makefile, [[
>  # a hook for preserving undef directive in config.h
> -- 
> 1.6.6.1
>