title: Basic signal handling in C++
body: <p>This is a pretty basic scenario but I'm not finding too many helpful resources. I have a C++ program running in Linux that does file processing. Reads lines, does various transformations, writes data into a database. There's certain variables (stored in the database) that affect the processing which I'm currently reading at every iteration because I want processing to be as up to date as possible, but a slight lag is OK. But those variables change pretty rarely, and the reads are expensive over time (10 million plus rows a day). I could space out the reads to every <em>n</em> iterations or simply restart the program when a variable changes, but those seem hackish.</p>
  
  <p>What I would like to do instead is have the program trigger a reread of the variables when it receives a SIGHUP. Everything I'm reading about signal handling is talking about the C signal library which I'm not sure how to tie in to my program's classes. The Boost signal libraries seem to be more about inter-object communication rather than handling OS signals.</p>
  
  <p>Can anybody help? It seems like this should be incredibly simple, but I'm pretty rusty with C++.</p>