Warning: NUMERIC_STD.TO_INTEGER: metavalue detected

[FPGAs]

metavalue in std_logic_vector

Warning: NUMERIC_STD.TO_INTEGER: metavalue detected, returning 0

My modelsim report it, why?
How can i solve it?
plese help me with some idea, thanks a lot!

 

[nand_gates]

modelsim vhdl warnings numeric_std metavalue

If ur passing std_logic_vector as a parameter to to_integer function and if
ur std_log_vector contains X or Z it will generate the warning you are getting.

To solve this one way is to never allow std_log_vector to contain any other
value than 0 or 1. Or use std_bit_vector!

 

[FPGAs]

explain to_integer function

Thanks to nand_gates.

I read a memo in Modelsim help, which is
"These messages can be turned off by setting the NumericStdNoWarnings variable to 1 from the command line or in the modelsim.ini file."

I turn off it in modelsim.ini file, but it don't affect, why?