Promoting char in comparison with RVCT

The default char will be promoted to int on WINSCW and unsigned on the RVCT compiler. Due to this promotion, comparison c != EOF will not become true on hardware and it will loop infinite.

RVCT treats plain char type as unsigned by default. There is a command line option "--signed_chars" that forces RVCT to treat plain char type as a signed char. Using this option, the example will compile and run the way it is expected to. But this option must be applied with care, since using the switch universally may have other ramifications elsewhere in the source base.

The MMP file can be modified as:

OPTION armcc  --signed_chars

Example:

#include <stdio.h>
int main()
{
  FILE *fp;
  char c;
  fp=fopen("test.txt","w"); 
  fprintf(fp,"%s","ab");
  fclose(fp);
  fp=fopen("test.txt","r"); 
  c=getc(fp);
  while(c != EOF)
  {
     c = getc(fp);
  }
  printf("\nOut of loop");
  fclose(fp);
  getchar();
}