Req #46145 [Opn]: printf() %e format should make 2 digit exponent
Edit report at https://bugs.php.net/bug.php?id=46145&edit=1
ID: 46145
User updated by: lbayuk at users dot sourceforge dot net
Reported by: lbayuk at users dot sourceforge dot net
Summary: printf() %e format should make 2 digit exponent
Status: Open
Type: Feature/Change Request
-Package: Feature/Change Request
+Package: *General Issues
Operating System: Linux
PHP Version: 5.2.6
Block user comment: N
Private report: N
New Comment:
(Verified still there in PHP-5.6.10 and fix email)
Previous Comments:
------------------------------------------------------------------------
[2008-09-29 01:07:30] lbayuk at pobox dot com
After taking a look at your patch, approximately:
/*
* Make sure the exponent has at least 2 digits
*/
+ if (t_len <= 1) {
+ *s++ = '0';
+ }
while (t_len--) {
I got curious, since the code you added is described by the existing comment. So I checked back
through CVS and sure enough similar code was there a while ago and was removed. It was:
if (t_len == 1)
*s++ = '0';
So it looks like the 2-digit minimum exponent code was *removed*. Certainly we would not want to put
the code back in until we determine why it came out... perhaps there was a good reason. I
haven't yet located the exact file version where the change was made.
------------------------------------------------------------------------
[2008-09-28 23:07:03] ilia dot cheishvili at gmail dot com
The patch to fix this is here, along with all of the unit tests that had to be modified to take the
new, correct behavior into account: http://pastebin.com/f641cf6fd
------------------------------------------------------------------------
[2008-09-21 19:44:25] lbayuk at users dot sourceforge dot net
Description:
------------
PHP printf, sprintf, and fprintf with %e scientific notation produce a 1 digit exponent for values
less than 1e10. Other implementation of functions by the same name produce a minimum of 2 digits in
the exponent, as the C standard requires. Although it can be argued that PHP is not bound by other
standards, the following comment in main/snprintf.c function php_conv_fp() [line 545] leads one to
believe this is a PHP bug:
/*
* Make sure the exponent has at least 2 digits
*/
Reproduce code:
---------------
<?php
printf("%8.2e\n", 1000000);
Expected result:
----------------
1.00e+06
Actual result:
--------------
<space>1.00e+6
------------------------------------------------------------------------
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