rlSpawn Class Reference

#include <rlspawn.h>

List of all members.

Public Member Functions
	rlSpawn ()
virtual	~rlSpawn ()
int	spawn (const char *command)
const char *	readLine ()
int	getchar ()
int	select (int timeout=50)
int	writeString (const char *buf)
int	write (const char *buf, int len)
int	printf (const char *format,...)
void	printAll ()
Public Attributes
int	pid
Private Attributes
void *	toChild
void *	fromChild
char	line [4096]

---

Detailed Description

Spawn an external program.
Redirect <stdin> <stdout> <stderr> of external program to this class

Now you can communicate with this external program over a pipe.
Attention: This class is only available on unix like systems.

Definition at line 32 of file rlspawn.h.

---

Constructor & Destructor Documentation

rlSpawn::rlSpawn

(

)

Definition at line 33 of file rlspawn.cpp.

{
  toChild = fromChild = NULL;
  pid = 0;
}

rlSpawn::~rlSpawn

(

)

[virtual]

Definition at line 39 of file rlspawn.cpp.

{
  if(toChild   != NULL) ::fclose((FILE*) toChild);
  if(fromChild != NULL) ::fclose((FILE*) fromChild);
}

---

Member Function Documentation

int rlSpawn::getchar

(

)

  Read a char from the spawned command.
  When the command terminates EOF is returned.
  

Definition at line 111 of file rlspawn.cpp.

{
  if(fromChild == NULL) return EOF;
  return ::fgetc((FILE*) fromChild);
}

void rlSpawn::printAll

(

)

  Print all outputs from spawned command to <stdout>
  

Definition at line 146 of file rlspawn.cpp.

{
  const char *cptr;
  while((cptr=readLine()) != NULL) ::printf("%s",cptr);
}

int rlSpawn::printf	(	const char *	format,
			...
	)

  similar to printf
  Return: number of bytes written
          -1 error
  

Definition at line 127 of file rlspawn.cpp.

{
  int ret;
  char message[rl_PRINTF_LENGTH]; // should be big enough

  va_list ap;
  va_start(ap,format);
  ret = rlvsnprintf(message, rl_PRINTF_LENGTH - 1, format, ap);
  va_end(ap);
  if(ret < 0) return ret;
  return write(message,strlen(message));
}

const char * rlSpawn::readLine

(

)

  Read a line from the spawned command.
  When the command terminates NULL is returned.
  

Definition at line 93 of file rlspawn.cpp.

{
  if(fromChild == NULL) return NULL;
  if(::fgets(line,sizeof(line)-1,(FILE*) fromChild) == NULL)
  {
#ifdef RLUNIX
    if(pid != 0)
    {
      int status;
      waitpid(pid, &status, 0);
      kill(pid,SIGHUP);
    }
#endif
    return NULL;
  }
  return line;
}

int rlSpawn::select

(

int

timeout = 50

)

  Wait for characters.
  return = 0 // timeout
  return = 1 // characters available
  

Definition at line 152 of file rlspawn.cpp.

{
#ifdef RLWIN32
  return -1;
#else
  struct timeval timout;
  fd_set wset,rset,eset;
  int    ret,maxfdp1,s;

  if(fromChild == NULL) return -1;
  s = fileno((FILE *) fromChild);
  /* setup sockets to read */
  maxfdp1 = s+1;
  FD_ZERO(&rset);
  FD_SET (s,&rset);
  FD_ZERO(&wset);
  FD_ZERO(&eset);
  timout.tv_sec  =  timeout / 1000;
  timout.tv_usec = (timeout % 1000) * 1000;

  ret = ::select(maxfdp1,&rset,&wset,&eset,&timout);
  if(ret == 0) return 0; /* timeout */
  return 1;
#endif  
}

int rlSpawn::spawn

(

const char *

command

)

  Start an operating system command.
  The output from the command can be read with readLine()
  You can write to the program with writeString() or write()
  Return: 0=success -1=error
  

Definition at line 45 of file rlspawn.cpp.

{
#ifdef RLWIN32 
  return -1;
#else  
  int to_child[2],from_child[2],ret;

  if(toChild   != NULL) ::fclose((FILE*) toChild);
  if(fromChild != NULL) ::fclose((FILE*) fromChild);
  toChild = fromChild = NULL;

  ret = ::pipe(to_child);
  if(ret == -1) return -1;
  ret = ::pipe(from_child);
  if(ret == -1) return -1;

  if((pid = ::fork()) == 0)
  {
    if(to_child[0] != 0) // stdin
    {
      ::dup2(to_child[0],0);
      ::close(to_child[0]);
    }
    if(from_child[1] != 2) // stderr
    {
      ::dup2(from_child[1] ,2);
    }
    if(from_child[1] != 1) // stdout
    {
      ::dup2(from_child[1],1);
      ::close(from_child[1]);
    }
    ::close(to_child[1]);
    ::close(from_child[0]);
    ::rlexec(command);
    ::exit(0);
  }

  ::close(to_child[0]);
  ::close(from_child[1]);
  toChild   = (void*) ::fdopen(to_child[1],"w");
  if(toChild == NULL)   {                            return -1; }
  fromChild = (void*) ::fdopen(from_child[0],"r");
  if(fromChild == NULL) { ::fclose((FILE*) toChild); return -1; }
  return pid;
#endif
}

int rlSpawn::write	(	const char *	buf,
		int	len
	)

  Write buf to <stdin> of spawned command
  Return: number of bytes written
          -1 error
  

Definition at line 117 of file rlspawn.cpp.

{
#ifdef RLWIN32
  return -1;
#else  
  if(toChild == NULL) return -1;
  return ::write(fileno((FILE*)toChild),buf,len);
#endif
}

int rlSpawn::writeString

(

const char *

buf

)

  Write buf to <stdin> of spawned command
  buf must be 0 terminated
  Return: number of bytes written
          -1 error
  

Definition at line 140 of file rlspawn.cpp.

{
  if(toChild == NULL) return -1;
  return fprintf((FILE*)toChild,"%s",buf);
}

---

Member Data Documentation

void * rlSpawn::fromChild [private]

Definition at line 95 of file rlspawn.h.

char rlSpawn::line[4096] [private]

Definition at line 96 of file rlspawn.h.

int rlSpawn::pid

Definition at line 92 of file rlspawn.h.

void* rlSpawn::toChild [private]

Definition at line 95 of file rlspawn.h.

---

The documentation for this class was generated from the following files:

• rlspawn.h
• rlspawn.cpp