Zsnes's zlib detection code problem.

colt (65)
Hi. I recently tried to build zsnes, however its zlib detection code seems to be seriously broken, as no matter how I pass it to configure, it won't detect it.

While I was not able to detect the precise code piece responsible for the problem, I have a few suspect. First I will copy configure's zlib code:

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if test "${with_zlib_prefix+set}" = set; then
  withval=$with_zlib_prefix; zlib_prefix="$withval"
else
  zlib_prefix=""
fi

min_zlib_version=1.2.3
{ echo "$as_me:$LINENO: checking for zlib - version >= $min_zlib_version" >&5
echo $ECHO_N "checking for zlib - version >= $min_zlib_version... $ECHO_C" >&6; }

tempLIBS="$LIBS"
tempCFLAGS="$CFLAGS"
if test x$zlib_prefix != x ; then
  ZLIB_LIBS="-L$zlib_prefix"
  ZLIB_CFLAGS="-I$zlib_prefix"
fi
ZLIB_LIBS="$ZLIB_LIBS -lz"
LIBS="$LIBS $ZLIB_LIBS"
CFLAGS="$CFLAGS $ZLIB_CFLAGS"

if test "$cross_compiling" = yes; then
  { echo "$as_me:$LINENO: result: cross-compiling" >&5
echo "${ECHO_T}cross-compiling" >&6; }
  with_zlib=""
  { echo "$as_me:$LINENO: WARNING: Assuming zlib is available" >&5
echo "$as_me: WARNING: Assuming zlib is available" >&2;}
else
  cat >conftest.$ac_ext <<_ACEOF
/* confdefs.h.  */
_ACEOF
cat confdefs.h >>conftest.$ac_ext
cat >>conftest.$ac_ext <<_ACEOF
/* end confdefs.h.  */

#include <zlib.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

char* my_strdup (char *str)
{
  char *new_str;

  if (str)
  {
    new_str = (char *)malloc ((strlen (str) + 1) * sizeof(char));
    strcpy (new_str, str);
  }
  else new_str = NULL;

  return new_str;
}

int main (int argc, char *argv[])
{
  int major, minor, micro, zlib_major_version, zlib_minor_version, zlib_micro_version;

  char *zlibver, *tmp_version;

  zlibver = ZLIB_VERSION;
	printf ("%c", ZLIB_VERSION);

  FILE *fp = fopen("conf.zlibtest", "a");
  if ( fp ) {
    fprintf(fp, "%s", zlibver);
    fclose(fp);
  }

  /* HP/UX 9 (%@#!) writes to sscanf strings */
  tmp_version = my_strdup("$min_zlib_version");
  if (sscanf(tmp_version, "%d.%d.%d", &major, &minor, &micro) != 3) {
    printf("%s, bad version string for\n\tmin_zlib_version... ", "$min_zlib_version");
    exit(1);
  }
  if (sscanf(zlibver, "%d.%d.%d", &zlib_major_version, &zlib_minor_version, &zlib_micro_version) != 3) {
    printf("%s, bad version string given\n", zlibver);
    puts("\tby zlib, sometimes due to very old zlibs that didnt correctly");
    printf("\tdefine their version. Please upgrade if you are running an\n\told zlib... ");
    exit(1);
  }

  if ((zlib_major_version > major) ||
     ((zlib_major_version == major) && (zlib_minor_version > minor)) ||
     ((zlib_major_version == major) && (zlib_minor_version == minor) && (zlib_micro_version >= micro)))
  {
    return 0;
  }
  else
  {
    return 1;
  }
}

_ACEOF
rm -f conftest$ac_exeext
if { (ac_try="$ac_link"
case "(($ac_try" in
  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
  *) ac_try_echo=$ac_try;;
esac
eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
  (eval "$ac_link") 2>&5
  ac_status=$?
  echo "$as_me:$LINENO: \$? = $ac_status" >&5
  (exit $ac_status); } && { ac_try='./conftest$ac_exeext'
  { (case "(($ac_try" in
  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
  *) ac_try_echo=$ac_try;;
esac
eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
  (eval "$ac_try") 2>&5
  ac_status=$?
  echo "$as_me:$LINENO: \$? = $ac_status" >&5
  (exit $ac_status); }; }; then
  with_zlib=yes
else
  echo "$as_me: program exited with status $ac_status" >&5
echo "$as_me: failed program was:" >&5
sed 's/^/| /' conftest.$ac_ext >&5

( exit $ac_status )
with_zlib=no
fi
rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext conftest.$ac_objext conftest.$ac_ext
fi



if test x$with_zlib != x; then
  { echo "$as_me:$LINENO: result: $with_zlib" >&5
echo "${ECHO_T}$with_zlib" >&6; }
fi
if test x$with_zlib = xyes; then
  ZLIB_VERSION=$(<conf.zlibtest)
  :
else
  ZLIB_CFLAGS=""
  ZLIB_LIBS=""
  ZLIB_VERSION=""
  { { echo "$as_me:$LINENO: error: zlib >= 1.2.3 is required" >&5
echo "$as_me: error: zlib >= 1.2.3 is required" >&2;}
   { (exit 1); exit 1; }; }
fi
LIBS="$tempLIBS"
CFLAGS="$tempCFLAGS"
rm conf.zlibtest


My main suspect was if (sscanf(tmp_version, "%d.%d.%d", &major, &minor, &micro) != 3) {. However, a few tests running a slight modified version of the c code isolated into a single file, didn't show me an awkward result from the variables of this line.

A few echos that I added to the test seems to indicate that the problem shows up from the point where the c code starts or latter.

So I am basically asking for suggestions on some lines of this piece of code to conduct experiments as to locate the precise cause of the problem.
Peter87 (11238)
Don't you get any error message telling you what goes wrong?

Is this something you put there yourself?
 
 
printf ("%c", ZLIB_VERSION);

GCC wrote:
warning: format ‘%c’ expects argument of type ‘int’, but argument 2 has type ‘char *’

Since ZLIB_VERSION is a string you probably want to use %s instead of %c.
Last edited on
colt (65)
Don't you get any error message telling you what goes wrong?


Besides: 
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configure:3798: WARNING: Assuming zlib is available
configure:3913: error: zlib >= 1.2.3 is required
. no

Is this something you put there yourself?


Yes.

I was able to run a lot of tests today using my own conftest and came to conclusion that the two most likely responsible lines are these two:

if (sscanf(tmp_version, "%d.%d.%d", &major, &minor, &micro) != 3) {
.
if (sscanf(zlibver, "%d.%d.%d", &zlib_major_version, &zlib_minor_version, &zlib_micro_version) != 3)

placing these two printf:


printf ("major.minor.micro: %d.%d.%d\n");
..
printf ("zlib_major_version.zlib_minor_version.zlib_micro_version: %d.%d.%d\n");

I receive this weird output:

major.minor.micro: 141205512.134515000.-143699968

zlib_major_version.zlib_minor_version.zlib_micro_version: 141205512.134515000.-143699968

..which seems weird.

This causes the execution of the the third if clause:



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if ((zlib_major_version > major) ||
     ((zlib_major_version == major) && (zlib_minor_version > minor)) ||
     ((zlib_major_version == major) && (zlib_minor_version == minor) && (zlib_micro_version >= micro)))
  {
		 printf ("BOTO3");
    return 0;
  }


However, thinking a bit more, it makes no difference, as these identical, weird triple numbers also satisfies the third comparison inside the if, as it would if the number versions were correct.

So the real problem might be beyond the c code, back in the shell script code.

P.S:I had to make a number of small modifications to be able to run my own conftest without shell script code.

The most important was probably this:

tmp_version = my_strdup("$min_zlib_version");

tmp_version = my_strdup("$1.2.3");

I executed an echo in the configure script that revealed that $min_zlib_version really evaluates to 1.2.3, as it should.

So it doesn't there is a problem with tmp_version or zlibver, which makes even weird these strange numbers being printed in the zlib_major_version, major etc, variables.

***RESUME*** While it appears to be a bug in the two sscanf line of codes, they would not be causing the issue, even by luck. The problem would lie ahead, back in the shell script code. However, as my own conftest code has to be a bit different so to allow me to execute it, I cannot be 100% sure.
Peter87 (11238)
You're not passing any arguments to match the %d.%d.%d in the printf format strings. That's why you saw garbage values. You probably meant to do the following:

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printf("%d.%d.%d\n", major, minor, micro);
printf("%d.%d.%d\n", zlib_major_version, zlib_minor_version, zlib_micro_version);


If you manually change 
 
 
tmp_version = my_strdup("$min_zlib_version");
to
 
 
tmp_version = my_strdup("$1.2.3");
then I think you should not include the $ inside the string.
Last edited on
colt (65)
Ok, I did the modifications suggested and the results were not very exciting: There is nothing wrong with the c code.

However ,there is a caveat. This is the c code of my own own test.c, not the one used by configure. So there is chance the cause is in the small differences between my test.c and the conftest.c. This seems unlikely, as the values printed in it or before, indicates that the values are correct and as expected. Still, would be nice if I could figure out a way print the values of conftest.c on the screen during configure's execution.

Another possibility is that the limitations of my system of running 32bit c or c++ programs are causing it. (this is a cross compilation attempt) However, these issues also showed up when trying to run configure to build a 64bit zsnes. So I discarded that for now.

All that added together leads to two possibilities:

1)Problem is happening in the shell script code that precedes the conftest.c code
2)Problem is happening in the shell script code that follows the conftest.c code.

As I already added a lot of checking statements in the preceding code (such as echo "printing variable a: $vara" and the values showed by them makes sense, the chances are greater that the problem lies in the following code. I still did not check the final part of the previous code, though.

As the following code is more difficult to understand than in the preceding code, I still did not make any substantial testing on it. As soon as I find more spare time, I will try to test it.

In the case anyone has interest, I pasted the full configure test below. Note my "ECHOs" after the CFLAGS line. To answer about the error messages, here is the output of configure related to zlib (from ZLIB:

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checking for zlib - version >= 1.2.3... ZLIB_CFLAGS: -I/media/34GB/Arquivos-de-Programas-Linux-32bit/Zlib-1.2.4/
ZLIB_LIBS: -L/media/34GB/Arquivos-de-Programas-Linux-32bit/Zlib-1.2.4/ -lz
ZLIB_VERSION: 
min_zlib_version: 1.2.3
LIBS:  -L/media/34GB/Arquivos-de-Programas-Linux-32bit/Zlib-1.2.4/ -lz
CFLAGS: -m32 -pipe -I. -I/usr/local/include -I/usr/include -D__UNIXSDL__ -I/media/34GB/Arquivos-de-Programas-Linux-32bit/Zlib-1.2.4/
cross-compiling
configure: WARNING: Assuming zlib is available
configure: error: zlib >= 1.2.3 is required


Note that there is nothing after ZLIB_VERSION:. That is because the value is pulled from zlib.h. Values printed during the executing of my test.c shows it is correct.

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if test "${with_zlib_prefix+set}" = set; then
  withval=$with_zlib_prefix; zlib_prefix="$withval"
else
  zlib_prefix=""
fi

min_zlib_version=1.2.3
{ echo "$as_me:$LINENO: checking for zlib - version >= $min_zlib_version" >&5
echo $ECHO_N "checking for zlib - version >= $min_zlib_version... $ECHO_C" >&6; }

tempLIBS="$LIBS"
tempCFLAGS="$CFLAGS"
if test x$zlib_prefix != x ; then
  ZLIB_LIBS="-L$zlib_prefix"
  ZLIB_CFLAGS="-I$zlib_prefix"
fi

ZLIB_LIBS="$ZLIB_LIBS -lz"
LIBS="$LIBS $ZLIB_LIBS"
CFLAGS="$CFLAGS $ZLIB_CFLAGS"
echo "ZLIB_CFLAGS: $ZLIB_CFLAGS"
echo "ZLIB_LIBS: $ZLIB_LIBS"
echo "ZLIB_VERSION: $ZLIB_VERSION"
echo "min_zlib_version: $min_zlib_version"
echo "LIBS: $LIBS"
echo "CFLAGS: $CFLAGS"


if test "$cross_compiling" = yes; then
  { echo "$as_me:$LINENO: result: cross-compiling" >&5
echo "${ECHO_T}cross-compiling" >&6; }
  with_zlib=""
  { echo "$as_me:$LINENO: WARNING: Assuming zlib is available" >&5
echo "$as_me: WARNING: Assuming zlib is available" >&2;}
else
  cat >conftest.$ac_ext <<_ACEOF
/* confdefs.h.  */
_ACEOF
cat confdefs.h >>conftest.$ac_ext
cat >>conftest.$ac_ext <<_ACEOF
/* end confdefs.h.  */

#include <zlib.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

char* my_strdup (char *str)
{
  char *new_str;

  if (str)
  {
    new_str = (char *)malloc ((strlen (str) + 1) * sizeof(char));
    strcpy (new_str, str);
  }
  else new_str = NULL;

  return new_str;
}

int main (int argc, char *argv[])
{
  int major, minor, micro, zlib_major_version, zlib_minor_version, zlib_micro_version;

  char *zlibver, *tmp_version;

  zlibver = ZLIB_VERSION;

  FILE *fp = fopen("conf.zlibtest", "a");
  if ( fp ) {
    fprintf(fp, "%s", zlibver);
    fclose(fp);
  }

  /* HP/UX 9 (%@#!) writes to sscanf strings */
  tmp_version = my_strdup("$min_zlib_version");
  if (sscanf(tmp_version, "%d.%d.%d", &major, &minor, &micro) != 3) {
    printf("%s, bad version string for\n\tmin_zlib_version... ", "$min_zlib_version");
    exit(1);
  }
  if (sscanf(zlibver, "%d.%d.%d", &zlib_major_version, &zlib_minor_version, &zlib_micro_version) != 3) {
    printf("%s, bad version string given\n", zlibver);
    puts("\tby zlib, sometimes due to very old zlibs that didnt correctly");
    printf("\tdefine their version. Please upgrade if you are running an\n\told zlib... ");
    exit(1);
  }

  if ((zlib_major_version > major) ||
     ((zlib_major_version == major) && (zlib_minor_version > minor)) ||
     ((zlib_major_version == major) && (zlib_minor_version == minor) && (zlib_micro_version >= micro)))
  {
    return 0;
  }
  else
  {
    return 1;
  }
}

_ACEOF
cp conf.zlibtest conf.zlibtest2
rm -f conftest$ac_exeext
if { (ac_try="$ac_link"
case "(($ac_try" in
  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
  *) ac_try_echo=$ac_try;;
esac
eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
  (eval "$ac_link") 2>&5
  ac_status=$?
  echo "$as_me:$LINENO: \$? = $ac_status" >&5
  (exit $ac_status); } && { ac_try='./conftest$ac_exeext'
  { (case "(($ac_try" in
  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
  *) ac_try_echo=$ac_try;;
esac
eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
  (eval "$ac_try") 2>&5
  ac_status=$?
  echo "$as_me:$LINENO: \$? = $ac_status" >&5
  (exit $ac_status); }; }; then
  with_zlib=yes
else
  echo "$as_me: program exited with status $ac_status" >&5
echo "$as_me: failed program was:" >&5
sed 's/^/| /' conftest.$ac_ext >&5

( exit $ac_status )
with_zlib=no
fi
rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext conftest.$ac_objext conftest.$ac_ext
fi

if test x$with_zlib != x; then
  { echo "$as_me:$LINENO: result: $with_zlib" >&5
echo "${ECHO_T}$with_zlib" >&6; }
fi
if test x$with_zlib = xyes; then
  ZLIB_VERSION=$(<conf.zlibtest)
  :
else
  ZLIB_CFLAGS=""
  ZLIB_LIBS=""
  ZLIB_VERSION=""
  { { echo "$as_me:$LINENO: error: zlib >= 1.2.3 is required" >&5
echo "$as_me: error: zlib >= 1.2.3 is required" >&2;}
   { (exit 1); exit 1; }; }
fi
LIBS="$tempLIBS"
CFLAGS="$tempCFLAGS"
rm conf.zlibtest


***EDITED***. Configure parameters: CFLAGS=-m32 ./configure --host=i686-gnu-linux --with-sdl-prefix=/media/34GB/Arquivos-de-Programas-Linux-32bit/Sdl-1.2.15/ --with-zlib-prefix=/media/34GB/Arquivos-de-Programas-Linux-32bit/Zlib-1.2.4/
Last edited on
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