It's skipping over ':' characters (which serve as delimiters) to get to the next token of the string (or end of line). So it looks correct, but the check for en

It's skipping over ':' characters (which serve as delimiters) to get to the next token of the string (or end of line). So it looks correct, but the check for end of line is superfluous (unless any architecture uses ':' as end of line marker of course). I think it is more likely it looks the way it does because it was made by copy-pasting and editing the loop a few lines further down that copies a token: while (categoryvalue[0] != '\0' && categoryvalue[0] != ':') *cp++ = *categoryvalue++; As for the shifting, I would assume glibc is free to expect whatever holds true on the platforms it currently supports. But fair enough warning about it in a analysis tool.