Including <termios.h> and <asm/termios.h> in the same project

Question

What I want to achieve: I want to set custom baud rate values for some tty*-like UART-mapped terminals.

How: The only way I found by far is to use the struct termios2 structure which is located in<asm/termios> header (as mentioned here, first answer).

My solution works very well by far, but now I need to use some functions:

speed_t cfgetispeed(const struct termios *);
int     tcdrain(int);
int     tcflow(int, int);
int     tcflush(int, int);
int     tcgetattr(int, struct termios *);
pid_t   tcgetsid(int);
int     tcsendbreak(int, int);
int     tcsetattr(int, int, struct termios *);

The problem is that in <asm/termios.h> there are no such functions, and I need to include <termios.h> for being able to use them.

Problem: If I include both headers (<asm/termios.h> and <termios.h>) the compiler will scream about functions and structure re-declaration, and he's right.

How can I solve this without using some obscure practice (like wrapping one of headers in a namespace, like mentioned here)?

Answer 1

How can I solve this without using some obscure practice (like wrapping one of headers in a namespace, like mentioned here)?

If you find namespaces obscure, I don't know how you'd call this:

#define termios asmtermios
#include <asm/termios.h>
#undef  termios
#include <termios.h>

Anyway, this too gets you rid of the error: redefinition of 'struct termios'.

Answer 2

I had a similar issue - wanted custom baud rate support with definitions like termios2, TCGETS2 and BOTHER, while still making use of the traditional termios calls. I instinctively wrapped the termios2 stuff in its own compilation unit and had no problems. So my structure looks like this:

serial_driver.c/.h

#include <termios.h>
#include <fcntl.h>
#include <dirent.h>

int open_port(int fd, int baudrate, eParitySetting parity, int numStopBits)
{
  if(baudrate_is_non_standard(baudrate)
    setNonStandardBaudRateTermios(fd, baudrate, parity, numStopBits);
  else
    //all the normal tcgetattr/cfsetospeed/tcsetattr
}

int do_other_things(void)
{
  //all the normal tcsendbreak/tcflush/etc things
}

serial_driver_abr.c/.h

#include <asm/termios.h> /* asm gives us the all important BOTHER and TCGETS2 */
#include <fcntl.h>
#include <dirent.h>
#include <stropts.h> /* Oddly, for ioctl, because ioctl.h causes include dramas */

setNonStandardBaudRateTermios(int fd, int baudrate, eParitySetting parity, int numStopBits)
{
  //All the termios2/ioctl/TCGETS2/BOTHER things
}

Works well for me.