Please try using this CVS snapshot:

  http://snaps.php.net/php4-STABLE-latest.tar.gz
 
For Windows:
 
  http://snaps.php.net/win32/php4-win32-STABLE-latest.zip

Tried latest CVS, exact same result.
Could be same problem as reported in bug #19588, as I tried to do a convert(smallmoney, amount) instead of float conversion and it still failed.

I've tested this with the latest code from CVS of both php4 and php5 and I can't reproduce it.

Please provide some more details like php.ini settings for mssql and are you using CGI or apache module ?

The Microsoft library used for the mssql extension is not thread safe. That could be the problem if you are using apache module.

You can send your sample code and data to fmk@php.net.

I've created a sample database with my table, along with this script:

<?
echo "Connect to server<br>";
$ConnID = mssql_pconnect('justin', 'xxx', 'ppp');
if ($ConnID===false) die("Cannot connect to server");
echo "select Database<br>";
if (!mssql_select_db('PhpMoneyTest')) die('cannot select db PHPmoneytest');
$sql="select amount as amount from Test";
$result = mssql_query($sql);

// php crashes here

echo "Test Passed"
// Finished

?>


php.ini settings are:
[MSSQL]
; Allow or prevent persistent links.
mssql.allow_persistent = on
; Maximum number of persistent links.  -1 means no limit.
mssql.max_persistent = -1
; Maximum number of links (persistent+non persistent).  -1 means no limit.
mssql.max_links = -1
; Minimum error severity to display.
mssql.min_error_severity = 10
; Minimum message severity to display.
mssql.min_message_severity = 10
; Compatability mode with old versions of PHP 3.0.
mssql.compatability_mode = Off
; Valid range 0 - 2147483647.  Default = 4096.
;[jvp] allow more text!
mssql.textlimit = 16384
; Valid range 0 - 2147483647.  Default = 4096.
;[jvp]
mssql.textsize = 16384
; Limits the number of records in each batch.  0 = all records in one batch.
mssql.batchsize = 0
; Use NT authentication when connecting to the server
mssql.secure_connection = 0
; Specify max number of processes. Default = 25
;mssql.max_procs = 25
; Disable date time conversions: dates formatted yyyy-mm-dd hh:mm:ssAA
mssql.datetimeconvert = 0

I tried changing some of these (in particular, tried without persistent connections) without any effect.

I'm using apache module, but this dies with only a single process (request), so its unlikely to be  a thread issue.  I'm very concerned about your threadsafe comments - can you point me to any discussion of this issue?

sample db with table 'Test' emailed as requested.

Thanks for your quick response!

Justin

Does it crash if you run it from command line using CLI / CGI binary?

running it from the command line ('php moneytest.php') also crashes:
dr watson:
function: RtlAllocateHeap
        77fcc4c9 897dcc           mov     [ebp+0xcc],edi         ss:0154958a=????????
        77fcc4cc 884705           mov     [edi+0x5],al                 ds:020da096=??
        77fcc4cf 66894f02         mov     [edi+0x2],cx               ds:020da097=????
        77fcc4d3 8a4e04           mov     cl,[esi+0x4]                 ds:020da076=??
        77fcc4d6 884f04           mov     [edi+0x4],cl                 ds:020da096=??
        77fcc4d9 66891f           mov     [edi],bx                   ds:00cc01b0=2e6c
        77fcc4dc a810             test    al,0x10
        77fcc4de 0f8540020000     jne     RtlAllocateHeap+0x477 (77fcc724)
        77fcc4e4 8d0cdf           lea     ecx,[edi+ebx*8]        ds:00002e6c=????????
        77fcc4e7 894dd0           mov     [ebp+0xd0],ecx         ss:0154958a=????????
FAULT ->77fcc4ea 8a4105           mov     al,[ecx+0x5]                 ds:020f13f6=??
        77fcc4ed a801             test    al,0x1
        77fcc4ef 0f8419ebffff     je      _eFSQRT+0xd44 (77fcb00e)
        77fcc4f5 66895902         mov     [ecx+0x2],bx               ds:020f13f7=????
        77fcc4f9 6681fb8000       cmp     bx,0x80
        77fcc4fe 0f8391f4ffff     jnb     RtlSizeHeap+0x8f (77fcb995)
        77fcc504 80670510         and     byte ptr [edi+0x5],0x10      ds:020da096=??
        77fcc508 0fb7c3           movzx   eax,bx
        77fcc50b 8b4da4           mov     ecx,[ebp+0xa4]         ss:0154958a=????????
        77fcc50e 8db4c178010000   lea     esi,[ecx+eax*8+0x178]  ds:000006e6=????????
        77fcc515 89b500ffffff     mov     [ebp+0xffffff00],esi   ss:0012f5a4=00000000
        77fcc51b 3936             cmp     [esi],esi              ds:00cc0190=00cc0004

*----> Stack Back Trace <----*

FramePtr ReturnAd Param#1  Param#2  Param#3  Param#4  Function Name
0012F6A4 100BFE82 00CC0000 00000001 00000018 00000001 ntdll!RtlAllocateHeap 
00000005 00000000 00000000 00000000 00000000 00000000 !emalloc

This bug has been fixed in CVS.

Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.
 
Thank you for the report, and for helping us make PHP better.

new version from CVS works fine now.  However returning a float instead of string may cause other programs to develop rounding problems.  AS PHP does not support Money type or fixed point arithmetic, this may just be as good as it gets.