Description:
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The documentation for file_get_contents() is wrong.  The default value 
of the maxlen param is stated to be -1 but, when looking at the C code, 
it is set to PHP_STREAM_COPY_ALL, not -1.  Passing -1 will trigger a 
warning and return false.

After looking at the C code, the default value is PHP_STREAM_COPY_ALL, 
not -1.

Reproduce code:
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$fileContents = file_get_contents('file.txt', 0, null, -1, -1);

Expected result:
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Get the entire file into $fileContents

Actual result:
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Warning: "length must be greater than or equal to zero"