semop

opinionated utility for easy use of SysV semaphore sets

Opinions

• SysV semaphores represent a pinnacle of IPC
• For most uses, a set of a single semaphore is adequate
• Shell scripts can benefit from semaphores
  • flock only goes so far
• Four letter identifiers are better than numeric ids

To build from source

CFLAGS=-O3 make semop

Usage

Usage: ./semop [OPTION] <semaphore ascii key>
  -i increment
  -d decrement, will wait
  -D decrement, will not wait (exits 1 on EAGAIN)
  -1 set to 1
  -z set to 0
  -0 return when 0, will wait
  -x delete semaphore set
  -p print current value
  -n print current value only if set exists

Usage: ./semop -s <int> <semaphore ascii key>
  -s  set to <int>

If no option is given, -p is assumed.
key is 1 to 4 ascii characters to be converted to a numeric id.