---
name: "redi_basic_ipstream"
section: "3"
platform: "linux"
package: "libpstreams-dev"
version: "1.0.3-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/redi_basic_ipstream"
---

# redi\_basic\_ipstream(3)

Class template for Input PStreams

## NAME

redi::basic\_ipstream - Class template for Input PStreams

## SYNOPSIS

`#include <pstream.h>`

Inherits basic\_istream\< CharT, std::char\_traits\< CharT \> \>, **redi::pstream\_common\< CharT, std::char\_traits\< CharT \> \>**, and **redi::pstreams**.

### Public Types

typedef pbase\_type::pmode **pmode**\
 Type used to specify how to connect to the process.  typedef pbase\_type::argv\_type **argv\_type**\
 Type used to hold the arguments for a command.  typedef int **fd\_type**\
 Type used for file descriptors.  typedef int **fd\_type**\
 Type used for file descriptors.

### Public Member Functions

**basic\_ipstream** ()\
 Default constructor, creates an uninitialised stream.  **basic\_ipstream** (const std::string &cmd, **pmode** mode=**pstdout**)\
 Constructor that initialises the stream by starting a process.  **basic\_ipstream** (const std::string &file, const **argv\_type** &argv, **pmode** mode=**pstdout**)\
 Constructor that initialises the stream by starting a process.  **basic\_ipstream** (const **argv\_type** &argv, **pmode** mode=**pstdout**)\
 Constructor that initialises the stream by starting a process.  **~basic\_ipstream** ()\
 Destructor.  void **open** (const std::string &cmd, **pmode** mode=**pstdout**)\
 Start a process.  void **open** (const std::string &file, const **argv\_type** &argv, **pmode** mode=**pstdout**)\
 Start a process.  **basic\_ipstream** & **out** ()\
 Set streambuf to read from process' `stdout`.  **basic\_ipstream** & **err** ()\
 Set streambuf to read from process' `stderr`.  int **close** ()\
 bool **is\_open** () const\
 Report whether the stream's buffer has been initialised.  const std::string & **command** () const\
 Return the command used to initialise the stream.  **streambuf\_type** \* **rdbuf** () const\
 Return a pointer to the stream buffer.

### Static Public Attributes

static const **pmode** **pstdin** = std::ios\_base::out\
 Write to stdin.  static const **pmode** **pstdout** = std::ios\_base::in\
 Read from stdout.  static const **pmode** **pstderr** = std::ios\_base::app\
 Read from stderr.  static const **pmode** **newpg** = std::ios\_base::trunc\
 Create a new process group for the child process.  static const **pmode** **pstdin** = std::ios\_base::out\
 Write to stdin.  static const **pmode** **pstdout** = std::ios\_base::in\
 Read from stdout.  static const **pmode** **pstderr** = std::ios\_base::app\
 Read from stderr.  static const **pmode** **newpg** = std::ios\_base::trunc\
 Create a new process group for the child process.

### Protected Types

typedef **basic\_pstreambuf**\< CharT, std::char\_traits\< CharT \> \> **streambuf\_type**\
 typedef std::basic\_ios\< CharT, std::char\_traits\< CharT \> \> **ios\_type**\
 enum { **bufsz** = 32 }\
 enum { **pbsz** = 2 }\
 enum { **bufsz** = 32 }\
 enum { **pbsz** = 2 }\

### Protected Member Functions

void **do\_open** (const std::string &cmd, **pmode** mode)\
 Start a process.  void **do\_open** (const std::string &file, const **argv\_type** &argv, **pmode** mode)\
 Start a process.

### Protected Attributes

std::string **command\_**\
 The command used to start the process.

## Detailed Description

### template\<typename CharT, typename Traits = std::char\_traits\<CharT\>\>

class redi::basic\_ipstream\< CharT, Traits \>" Class template for Input PStreams.

Reading from an ipstream reads the command's standard output and/or standard error (depending on how the ipstream is opened) and the command's standard input is the same as that of the process that created the object, unless altered by the command itself.

## Constructor & Destructor Documentation

### template\<typename CharT , typename Traits = std::char\_traits\<CharT\>\> redi::basic\_ipstream\< CharT, Traits \>::basic\_ipstream (const std::string & cmd, pmode mode = pstdout)` [inline]`, ` [explicit]`

Constructor that initialises the stream by starting a process. Initialises the stream buffer by calling **do\_open()** with the supplied arguments.

**Parameters**

*cmd* a string containing a shell command. \
 *mode* the I/O mode to use when opening the pipe.

**See also**

**do\_open(const std::string&, pmode)**

### template\<typename CharT , typename Traits = std::char\_traits\<CharT\>\> redi::basic\_ipstream\< CharT, Traits \>::basic\_ipstream (const std::string & file, const argv\_type & argv, pmode mode = pstdout)` [inline]`

Constructor that initialises the stream by starting a process. Initialises the stream buffer by calling **do\_open()** with the supplied arguments.

**Parameters**

*file* a string containing the pathname of a program to execute. \
 *argv* a vector of argument strings passed to the new program. \
 *mode* the I/O mode to use when opening the pipe.

**See also**

**do\_open(const std::string&, const argv\_type&, pmode)**

### template\<typename CharT , typename Traits = std::char\_traits\<CharT\>\> redi::basic\_ipstream\< CharT, Traits \>::basic\_ipstream (const argv\_type & argv, pmode mode = pstdout)` [inline]`, ` [explicit]`

Constructor that initialises the stream by starting a process. Initialises the stream buffer by calling `do_open`(argv\[0\],argv,mode\|pstdout)

**Parameters**

*argv* a vector of argument strings passed to the new program. \
 *mode* the I/O mode to use when opening the pipe.

**See also**

**do\_open(const std::string&, const argv\_type&, pmode)**

### template\<typename CharT , typename Traits = std::char\_traits\<CharT\>\> redi::basic\_ipstream\< CharT, Traits \>::~basic\_ipstream ()` [inline]`

Destructor. Closes the stream and waits for the child to exit.

## Member Function Documentation

### int redi::pstream\_common\< C, T \>::close` [inline]`, ` [inherited]`

Close the pipe, returning the program's exit status, as [pclose(3)](/pclose/3.md) does.

Calls rdbuf-\>**close()** and sets `failbit` on error. Returns process's exit status, as [pclose(3)](/pclose/3.md) does.

### const std::string & redi::pstream\_common\< C, T \>::command` [inline]`, ` [inherited]`

Return the command used to initialise the stream.

**Returns**

a string containing the command used to initialise the stream.

### void redi::pstream\_common\< C, T \>::do\_open (const std::string & cmd, pmode mode)` [inline]`, ` [protected]`, ` [inherited]`

Start a process. Calls **rdbuf()**-\>open( *command* , *mode* ) and sets `failbit` on error.

**Parameters**

*cmd* a string containing a shell command. \
 *mode* the I/O mode to use when opening the pipe.

**See also**

**basic\_pstreambuf::open(const std::string&, pmode)**

### void redi::pstream\_common\< C, T \>::do\_open (const std::string & file, const argv\_type & argv, pmode mode)` [inline]`, ` [protected]`, ` [inherited]`

Start a process. Calls **rdbuf()**-\>open( *file*, *argv*, *mode* ) and sets `failbit` on error.

**Parameters**

*file* a string containing the pathname of a program to execute. \
 *argv* a vector of argument strings passed to the new program. \
 *mode* the I/O mode to use when opening the pipe.

**See also**

**basic\_pstreambuf::open(const std::string&, const argv\_type&, pmode)**

### template\<typename CharT , typename Traits = std::char\_traits\<CharT\>\> basic\_ipstream& redi::basic\_ipstream\< CharT, Traits \>::err ()` [inline]`

Set streambuf to read from process' `stderr`.

**Returns**

`*this`

References redi::basic\_pstreambuf\< CharT, Traits \>::read\_err().

### bool redi::pstream\_common\< C, T \>::is\_open` [inline]`, ` [inherited]`

Report whether the stream's buffer has been initialised.

**Returns**

**rdbuf()**-\>**is\_open()**.

**See also**

**basic\_pstreambuf::is\_open()**

### template\<typename CharT , typename Traits = std::char\_traits\<CharT\>\> void redi::basic\_ipstream\< CharT, Traits \>::open (const std::string & cmd, pmode mode = pstdout)` [inline]`

Start a process. Calls do\_open( *cmd* , *mode\|pstdout* ).

**Parameters**

*cmd* a string containing a shell command. \
 *mode* the I/O mode to use when opening the pipe.

**See also**

**do\_open(const std::string&, pmode)**

References redi::pstream\_common\< CharT, std::char\_traits\< CharT \> \>::do\_open().

### template\<typename CharT , typename Traits = std::char\_traits\<CharT\>\> void redi::basic\_ipstream\< CharT, Traits \>::open (const std::string & file, const argv\_type & argv, pmode mode = pstdout)` [inline]`

Start a process. Calls do\_open( *file* , *argv* , *mode\|pstdout* ).

**Parameters**

*file* a string containing the pathname of a program to execute. \
 *argv* a vector of argument strings passed to the new program. \
 *mode* the I/O mode to use when opening the pipe.

**See also**

**do\_open(const std::string&, const argv\_type&, pmode)**

References redi::pstream\_common\< CharT, std::char\_traits\< CharT \> \>::do\_open().

### template\<typename CharT , typename Traits = std::char\_traits\<CharT\>\> basic\_ipstream& redi::basic\_ipstream\< CharT, Traits \>::out ()` [inline]`

Set streambuf to read from process' `stdout`.

**Returns**

`*this`

References redi::basic\_pstreambuf\< CharT, Traits \>::read\_err().

### pstream\_common\< C, T \>::streambuf\_type \* redi::pstream\_common\< C, T \>::rdbuf` [inline]`, ` [inherited]`

Return a pointer to the stream buffer.

**Returns**

a pointer to the private stream buffer member.

## Author

Generated automatically by Doxygen for PStreams from the source code.