UT_WritePipe Class Reference

#include <UT_WritePipe.h>

Public Member Functions
	UT_WritePipe (const char *cmd=0, bool change_process_group=false)
	~UT_WritePipe ()
FILE *	open (const char *cmd)
FILE *	open (const char *cmd, FILE *kid_stdout, FILE *kid_stderr)
int	close (bool wait_for_child_to_terminate=false)
bool	isComplete (bool block=false)
void	suspend ()
	Suspend pipe process. More...
void	restart ()
	Restart pipe process after suspended. More...
false is liable *to return false if you call it right after this Use *	isComplete (true)`to ensure the pipe process is fully *complete before continuing
false is liable *to return false if you call it right after this Use or call	close ()`with block set to true.*/void terminate()
bool	isSuspended () const
	Is pipe process suspended? More...
FILE *	getFilePtr ()
	Return file handle for last open() call. More...
int	getErrno () const
int	getStatus () const
pid_t	getPid () const
	This method will return the child process id. More...

Detailed Description

Examples:

FS/FS_Background.C.

Definition at line 30 of file UT_WritePipe.h.

Constructor & Destructor Documentation

UT_WritePipe::UT_WritePipe ( const char *  cmd = 0, bool  change_process_group = false  )

explicit

Construct pipe

Parameters

cmd	If given, opens the cmd before returning. Call getFilePtr() for the actual created file handle.
change_process_group	Puts the child process in a new process group to isolate the parent from any crashes coming from the child.

UT_WritePipe::~UT_WritePipe

(

)

Destruct pipe

If the pipe is open and destructed, the process will be blocked until the child is terminated.

Member Function Documentation

int UT_WritePipe::close

(

bool

wait_for_child_to_terminate = false

)

Close the pipe

Returns

Return values are:

• -1 : Error closing the pipe
• 0 : Child is still running (only returned if the arg is 0)
• >0 : Child is terminated

Note

After close is called, it is not safe to write to the pipe anymore (since the file descriptor is closed). Please use isComplete() to see if the child process has terminated.

Examples:

FS/FS_Background.C.

false is liable* to return false if you call it right after this Use or call UT_WritePipe::close

(

)

int UT_WritePipe::getErrno ( ) const

inline

If close() fails, you can get the errno of the fail call by calling this method. If the child is still running, the error will be set to EWOULDBLOCK

Definition at line 103 of file UT_WritePipe.h.

FILE* UT_WritePipe::getFilePtr ( )

inline

Return file handle for last open() call.

Definition at line 98 of file UT_WritePipe.h.

pid_t UT_WritePipe::getPid ( ) const

inline

This method will return the child process id.

Definition at line 110 of file UT_WritePipe.h.

int UT_WritePipe::getStatus ( ) const

inline

If close() succeeds, you can get the exit status of the child process by calling the following method.

Definition at line 107 of file UT_WritePipe.h.

bool UT_WritePipe::isComplete

(

bool

block = false

)

Call this to find out whether it's safe to close (i.e. the child process has terminated). This can be called before, or after the pipe has been closed.

Examples:

FS/FS_Background.C.

false is liable* to return false if you call it right after this Use* UT_WritePipe::isComplete

(

true

)

Terminate pipe process

Warning

This method is asynchronous! `close(/*block

bool UT_WritePipe::isSuspended

(

)

const

Is pipe process suspended?

FILE* UT_WritePipe::open ( const char *  cmd )

inline

Open a command as a write pipe. The file descriptor returned will be the command's stdin.

Examples:

FS/FS_Background.C.

Definition at line 52 of file UT_WritePipe.h.

FILE* UT_WritePipe::open	(	const char *	cmd,
		FILE *	kid_stdout,
		FILE *	kid_stderr
	)

Open a command as a write pipe. The file descriptor returned will be the command's stdin. If the kid_stdout file descriptor is given, this will become stdout for the child. If kid_stderr is specified, it will be come stderr for the child.

void UT_WritePipe::restart

(

)

Restart pipe process after suspended.

void UT_WritePipe::suspend

(

)

Suspend pipe process.

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

• UT/UT_WritePipe.h