wrp@krebs.acc.Virginia.EDU (Bill Pearson) (02/18/90)
I recently converted a program that scans and analyzes the contents of at 4 mbyte file from Think 'C' to MPW 'C', in order to take advantage of 32 bit ints. To my surprise, the program was about 1/2 as fast under MPW 'C' (running under the MPW shell). Even when the program was compiled to use 68020 codes, it still took 50% longer to run. My Think version used to take about twice as long, until I increased the file read buffer size with setvbuf(). I have also done this with the MPW version, but I am suspicious that setvbuf() may not really work under MPW C 3.0. I note that in stdio.h, the FILE data structure only uses an unsigned short for the buffer size. Since MPW C does not supply source for the libraries, I cannot check. Thus, I have two questions: Does the MPW shell slow things down substantially? Does setvbuf() work properly under MPW 'C'? (Really I only have one question, how do I make my program run as fast under MPW as it does under Think 'C'?) Bill Pearson