gpioread

Macros
#define	APP_EC_OK   0
	success exit code
#define	APP_EC_ARGS   2
	command-line options/arguments error exit code
#define	APP_EC_EXEC   4
	execution exit code

Functions
static int	strToInt (const string &str, int &val)
static void	printValue (int val)
static void	mainInit (int argc, char *argv[])
	Main initialization. More...
static int	sysfsRead ()
	Read GPIO value(s). More...
int	main (int argc, char *argv[])
	Main. More...

Variables
static char *	Argv0
	the command
static char *	OptsMethod = (char *)"sysfs"
	system file system
static int	OptsCount = 1
	number of reads
static double	OptsInterval = 1.0
	read interval in seconds
static bool_t	OptsVerbose = false
	permissions
static int	ArgsGpio
	gpio number
static OptsPgmInfo_T	PgmInfo
	Program information. More...
static OptsInfo_T	OptsInfo []
	Command line options information.

Detailed Description

Function Documentation

int main	(	int	argc,
		char *	argv[]
	)

Main.

Parameters

argc	Command-line argument count.
argv	Command-line argument list.

Returns

Returns 0 on succes, non-zero on failure.

Definition at line 324 of file gpioread.cxx.

References APP_EC_ARGS, mainInit(), OptsMethod, and sysfsRead().

{
  int   ec;

  mainInit(argc, argv);

  if( !strcmp(OptsMethod, "sysfs") )
  {
    ec = sysfsRead();
  }

#ifdef MMAP_GPIO
  else if( !strcmp(OptsMethod, "mmap") )
  {
    ec = mmapRead();
  }
#endif // MMAP_GPIO

  else
  {
    fprintf(stderr,"%s: Unknown GPIO access method.", OptsMethod);
    ec = APP_EC_ARGS;
  }

  return ec;
}

static void mainInit ( int  argc, char *  argv[]  )

static

Main initialization.

Parameters

argc	Command-line argument count.
argv	Command-line argument list.

Exits:

Program terminates on conversion error.

Definition at line 188 of file gpioread.cxx.

References APP_EC_ARGS, ArgsGpio, Argv0, OptsCount, OptsInfo, OptsInterval, PgmInfo, and PkgInfo.

Referenced by main().

{
  // name of this process
  Argv0 = basename(argv[0]);

  // parse input options
  argv = OptsGet(Argv0, &PkgInfo, &PgmInfo, OptsInfo, true, &argc, argv);

  if( OptsCount < 0 )
  {
    OptsCount = -OptsCount;
  }

  if( OptsInterval < 0.0 )
  {
    OptsInterval = -OptsInterval;
  }

  if( argc == 0 )
  {
    fprintf(stderr, "%s: No GPIO pin number <gpio> specified.\n", Argv0);
    fprintf(stderr, "Try '%s --help' for more information.\n", Argv0);
    exit(APP_EC_ARGS);
  }

  else if( strToInt(argv[0], ArgsGpio) < 0 )
  {
    fprintf(stderr, "%s: '%s': Bad GPIO number.\n", Argv0, argv[0]);
    fprintf(stderr, "Try '%s --help' for more information.\n", Argv0);
    exit(APP_EC_ARGS);
  }
}

static int sysfsRead ( )

static

Read GPIO value(s).

Method: sysfs

Returns

Application exit code.

Definition at line 228 of file gpioread.cxx.

References APP_EC_EXEC, APP_EC_OK, ArgsGpio, gpioClose(), gpioOpen(), gpioQuickRead(), OptsCount, and OptsInterval.

Referenced by main().

{
  int         fd;
  bool        bForever;
  int         nReads;
  int         val;
  uint_t      usec;

  if( (fd = gpioOpen(ArgsGpio)) < 0 )
  {
    return APP_EC_EXEC;
  }

  bForever  = OptsCount == 0? true: false;
  nReads    = 0;
  usec      = (uint_t)(OptsInterval * 1000000);
  
  while( bForever || (nReads < OptsCount) )
  {
    if( (nReads > 0) && (usec > 0) )
    {
      usleep(usec);
    }

    if( (val = gpioQuickRead(fd)) < 0 )
    {
      gpioClose(fd);
      return APP_EC_EXEC;
    }

    printValue(val);

    ++nReads;
  }

  gpioClose(fd);

  return APP_EC_OK;
}

Variable Documentation

OptsPgmInfo_T PgmInfo

static

Initial value:

=
{
  
  "<gpio>",

  
  "Read GPIO pin value.",

  
  "The %P command reads the current GPIO pin value (0 or 1) for the specified "
  "GPIO exported number.",

  
  NULL
}

Program information.

Definition at line 70 of file gpioread.cxx.

Referenced by mainInit().