The function does not return the same value as snprintf() normally does,
so readers may be mislead into thinking the code works differently than
it actually does. A different function name makes this easier to detect.
Reported-by: Tomas Hoger
Assisted-by: Daniel Gustafsson
Fixes#3296Closes#3297
The gcc typecheck macros and coverity combined made it warn on the 2nd
argument for ERROR_CHECK_SETOPT(). Here's minor rearrange to please it.
Coverity CID 1439115 and CID 1439114.