Massive fprintf speed difference without “-std=c99”

Question

I had been struggling for weeks with a poor-performing translator I had written. On the following simple bechmark

#include

int main()
{
    i         


        

Answer 1

Using -std=c99 disable all GNU extensions.

With GNU extensions and optimization, your fprintf(test, "B") is probably replaced by a fputc('B', test)

Note this answer is obsolete, see https://stackoverflow.com/a/13973562/611560 and https://stackoverflow.com/a/13973933/611560