Subversion Repositories SvarDOS

static unsigned char is_stdout_redirected(void) {

static unsigned char is_stdout_redirected(void);

  union REGS r;

#pragma aux is_stdout_redirected = \

  r.x.ax = 0x4400;                 /* DOS 2+, IOCTL Get Device Info */

"mov ax, 0x4400"    /* DOS 2+, IOCTL Get Device Info */            \

  r.x.bx = 0x0001;                 /* file handle (stdout) */

"mov bx, 0x0001"    /* file handle (stdout) */                     \

"int 0x21" \

  intdos(&r, &r);     /* Clib function to invoke DOS int21h call   */

"jc DONE"           /* on error AL contains a non-zero err code */ \

  if (r.x.cflag != 0) return(FILE_TYPE_UNKNOWN);

"and dl, 0x80"      /* bit 7 of DL is the "CHAR" flag */           \

  /* if bit 7 is set it is a char dev (not redirected to disk) */

"xor dl, 0x80"      /* return 0 if CHAR bit is set */              \

  if (r.x.dx & 0x80) return(0);

"mov al, dl" \

"DONE:" \

  /* assume valid file handle */

modify [ax bx dx] \

  return(1);

value [al]