minimum float value

[Mark P]

I have a float value which should be initialized to the minimum allowed
value (analogous to -infinity). I discovered today (thank you, unit
tests!) that numeric_limits< float>::min() returns a very small number
greater than 0, rather than the extremely negative number which I want.
Is it safe to use -numeric_limits< float>::max() for this purpose, or
is something else preferred?
Thanks,
Mark

[Greg Buchholz]

Mark P wrote:

I have a float value which should be initialized to the minimum allowed
value (analogous to -infinity).

What about actually using -infinity?

float init = numeric_limits< float>::has_inf inity
? -numeric_limits< float>::infinit y()
: -numeric_limits< float>::max();

I discovered today (thank you, unit
tests!) that numeric_limits< float>::min() returns a very small number
greater than 0, rather than the extremely negative number which I want.
Is it safe to use -numeric_limits< float>::max() for this purpose

In general? I suppose no. In practice, if your "float" represents
an IEEE754/854 number (a very common floating point standard), then you
should be safe, since a sign bit stored separately (no two's
complement).

Greg Buchholz