warning: comparison of unsigned expression >= 0 is always true

Question

I have the following error when compiling a C file:

t_memmove.c: In function ‘ft_memmove’:
ft_memmove.c:19: warning: comparison of unsigned expression >=          


        

Answer 1

consider this loop:

for(unsigned int i=5;i>=0;i--)
{

}

This loop will be infinite because whenever i becomes -1 it'll be interprated as a very large possitive value as sign bit is absent in unsigned int.

This is the reason a warning is generated here