How to read environment variable in Glibc code

[naveen yadav <yad.naveen@xxxxxxxxx>]

Dear All,

I want to disable/enable printf out put to screen by reading
environment variable similar to LD_DEBUG.

I want to control ./stdio-common/printf.c.

So if in environment variable says disable printf it call
int
__printf (const char *format, ...)
{
return done;

}

else it execute original code.

Thanks