Sometimes you need to work with big numbers in PHP (gulp). For example, sometimes 32-bit identifiers are not enough and you have to use BIGINT 64-bit ids; e.g. if you are encoding additional information like the server ID into high bits of the ID.
I had already written about the mess that 64-bit integers are in PHP. But if the numbers you use do not cover 64-bit range fully, floats might save the day. The trick is that PHP floats are in fact doubles, i.e. double-precision 64-bit numbers. They have 52 bits for mantissa, and integer values up to 2^53-1 can be stored exactly. So if you're using up to 53 bits, you're OK with floats.
However, there's a conversion caveat you should be aware of.
On different systems, float is converted to string differently. (I spent a bit of time fighting with it today.) Consider the following script:
PLAIN TEXT
<div class="syntax_hilite">CODE:<div id="code-6"><div class="code"><ol><li style="font-family: 'Courier New', Courier, monospace; color: black; font-weight: normal; font-style: normal;color:#3A6A8B;"><div style="font-family: 'Courier New', Courier, monospace; font-weight: normal;">