Function Perl_pregexec 

pub unsafe fn Perl_pregexec(
    my_perl: *mut PerlInterpreter,
    prog: *mut REGEXP,
    stringarg: *mut c_char,
    strend: *mut c_char,
    strbeg: *mut c_char,
    minend: isize,
    screamer: *mut SV,
    nosave: U32,
) -> I32

thx shim for crate::Perl_pregexec.