phrSetErrorFileName(filename)

# This example attempts to run a input string, fails and writes
# the error message to the error file (no database is loaded).
phrSetErrorFileOn(TRUE)
phrSetErrorFileName(file.path(tempdir(), "phreeqc.errors"))
input <- c( 
  'SOLUTION 1 Pure water ',
  'EQUILIBRIUM_PHASES 1  ',
  '    Calcite 0 10      '
  )

if (is.null(phrRunString(input))) {
  cat(paste("see ", phrGetErrorFileName(), ".\n", sep = ""))
}