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Other incompatibilities Short-circuited boolean evaluation

Last updated: Sat, 27 Jan 2007

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# Function `TRUE`/`FALSE` return values

Most internal functions have been rewritten so they return `TRUE` when successful and `FALSE` when failing, as opposed to 0 and -1 in PHP/FI 2.0, respectively. The new behaviour allows for more logical code, like `$fp = fopen("/your/file") or fail("darn!");`. Because PHP/FI 2.0 had no clear rules for what functions should return when they failed, most such scripts will probably have to be checked manually after using the 2.0 to 3.0 convertor.

Пример D-9. Migration from 2.0: return values, old code

`$fp = fopen($file, "r"); if ($fp == -1); echo("Could not open $file for reading<br />\n"); endif;`

Пример D-10. Migration from 2.0: return values, new code

`$fp = @fopen($file, "r") or print("Could not open $file for reading<br />\n");`

add a note User Contributed Notes
Function TRUE/FALSE return values
oliver at hankeln-online dot de
07-Aug-2002 08:22
`I guess you are indeed wrong. You are right, 'FALSE' is beeing evaluated as a string. But it is compared with a number, so automatic type conversion takes place. 'FALSE' as well as 'FOO' and so on are converted to 0. And (0==0) is obviously true. So the number does matter. Try an other number...
Oliver`
wildpeaks at warpdawg dot com
06-Aug-2002 07:30
`'FALSE' is interpreted as a string containing the word false and not as a boolean value, and comparing a non-null string to a number, whatever the number is, returns true (i may be wrong).`
dtampe at groupadress dot com
25-Oct-2001 10:27
`Try this:
if(0=='FALSE')
echo "It works but it should not work";
1 days of headheache...
Hope it helps!
DamTam`
add a note
Other incompatibilities Short-circuited boolean evaluation

Last updated: Sat, 27 Jan 2007
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