---
name: "ost_AppLog"
section: "3"
platform: "linux"
package: "libcommoncpp2-doc"
version: "1.8.1-10"
release: "Debian 11 (Bullseye)"
platforms: ["linux"]
url: "https://new.carta.tech/ost_AppLog"
---

# ost\_AppLog(3)

Application logger is a class that implements a logger that can be used by applications to save log file somewhere on the system.

## NAME

ost::AppLog - Application logger is a class that implements a logger that can be used by applications to save log file somewhere on the system.

## SYNOPSIS

`#include <applog.h>`

Inherits streambuf, and ostream.

### Classes

class **Ident**\
 **Ident** class that represents module name.

### Public Member Functions

**AppLog** (const char \***logFileName**=NULL, bool logDirectly=false, bool usePipe=false)\
 Constructor for a customized logger.  virtual **~AppLog** ()\
 Destructor.  void **subscribe** ()\
 Subscribes the current thread to logger, it reserves thread safe buffer for it.  void **unsubscribe** ()\
 Unsubscribes the current thread from logger.  void **logFileName** (const char \*FileName, bool logDirectly=false, bool usePipe=false)\
 Allows to set up **ost::alog** parameters.  void **close** (void)\
 if logDirectly is set it closes the file.  void **level** (**Slog::Level** enable)\
 Sets the log level.  void **clogEnable** (bool en=true)\
 Enables clog output.  void **slogEnable** (bool en=true)\
 Enables slog output for error level messages.  void **identLevel** (const char \*ident, **Slog::Level** **level**)\
 Sets the level for that ident.  void **open** (const char \*ident)\
 Opens the file if not already and sets ident.  virtual int **overflow** (int c)\
 stream **overflow()** overload.  virtual int **sync** ()\
 stream **sync()** overload  void **emerg** (const char \*format,...)\
 emerg level printf style method, provided for convenience.  void **alert** (const char \*format,...)\
 alert level printf style method, provided for convenience.  void **critical** (const char \*format,...)\
 critical level printf style method, provided for convenience.  void **error** (const char \*format,...)\
 error level printf style method, provided for convenience.  void **warn** (const char \*format,...)\
 warn level printf style method, provided for convenience.  void **notice** (const char \*format,...)\
 notice level printf style method, provided for convenience.  void **info** (const char \*format,...)\
 info level printf style method, provided for convenience.  void **debug** (const char \*format,...)\
 debug level printf style method, provided for convenience.  **AppLog** & **operator()** (const char \*ident, **Slog::Level** **level**=**Slog::levelError**)\
 operator to change ident and log level  **AppLog** & **operator()** (**Ident** &ident)\
 operator to change ident  **AppLog** & **operator()** (**Slog::Level** **level**)\
 operator to change logging level  **AppLog** & **operator\<\<** (**AppLog** &(\*pfManipulator)(**AppLog** &))\
 manipulator operator, to change print levels.  **AppLog** & **operator\<\<** (ostream &(\*pfManipulator)(ostream &))\
 manipulator operator, to use ostream manipulators (i.e.  **AppLog** & **operator\<\<** (**Ident** &ident)\
 operator \<\<  **AppLog** & **warn** (void)\
 warn level  **AppLog** & **error** (void)\
 error level  **AppLog** & **debug** (void)\
 debug level  **AppLog** & **emerg** (void)\
 emerg level  **AppLog** & **alert** (void)\
 alert level  **AppLog** & **critical** (void)\
 critical level  **AppLog** & **notice** (void)\
 notice level  **AppLog** & **info** (void)\
 info level

### Static Public Member Functions

static **Slog::Level** **levelTranslate** (string name)\
 Translates level from string to **Slog::Level**, useful for configuration files for instance.

### Protected Member Functions

void **writeLog** (bool endOfLine=true)\

### Protected Attributes

AppLogPrivate \* **d**\

### Static Protected Attributes

static map\< string, **Slog::Level** \> \* **assoc**\

### Friends

ostream & **operator\<\<** (ostream &out, **AppLog** &al)\

## Detailed Description

Application logger is a class that implements a logger that can be used by applications to save log file somewhere on the system.

It uses **ost::slog** to write to syslog and std::clog to write to standard output.

It provides either a stream oriented logger or a old printf style one.

It can be used to log directly on a file or in a spooler like way. Latter uses a **ost::ThreadQueue** to implement a thread safe access to logger.

It provides a global stream variable called **ost::alog**.

It provides an **AppLog::Ident** class that represents a module name for instance that can be used to tag logs. Logging levels are the same defined into **ost::Slog**: **Slog::levelEmergency** **Slog::levelAlert** **Slog::levelCritical** **Slog::levelError** **Slog::levelWarning** **Slog::levelNotice** **Slog::levelInfo** Slog::levelDebugfrom.

Example of usage: alog \<\< mod\_name \<\< debug \<\< 'Hello world!' \<\< std::endl;

## Constructor & Destructor Documentation

### ost::AppLog::AppLog (const char \* logFileName = `NULL`, bool logDirectly = `false`, bool usePipe = `false`)

Constructor for a customized logger.

**Parameters**

*logFileName* log file name. \
 *logDirectly* true to write directly to file, false to use a spooler like logger. \
 *usePipe* true to use pipe instead of file, false otherwise

### virtual ost::AppLog::~AppLog ()` [virtual]`

Destructor.

## Member Function Documentation

### void ost::AppLog::alert (const char \* format, ...)

alert level printf style method, provided for convenience.

**Parameters**

*format* printf format

### AppLog& ost::AppLog::alert (void)` [inline]`

alert level

**Returns**

application logger stream

### void ost::AppLog::clogEnable (bool en = `true`)

Enables clog output.

**Parameters**

*en* true to enable clog output.

### void ost::AppLog::close (void)

if logDirectly is set it closes the file.

### void ost::AppLog::critical (const char \* format, ...)

critical level printf style method, provided for convenience.

**Parameters**

*format* printf format

### AppLog& ost::AppLog::critical (void)` [inline]`

critical level

**Returns**

application logger stream

### void ost::AppLog::debug (const char \* format, ...)

debug level printf style method, provided for convenience.

**Parameters**

*format* printf format

### AppLog& ost::AppLog::debug (void)` [inline]`

debug level

**Returns**

application logger stream

### void ost::AppLog::emerg (const char \* format, ...)

emerg level printf style method, provided for convenience.

**Parameters**

*format* printf format

### AppLog& ost::AppLog::emerg (void)` [inline]`

emerg level

**Returns**

application logger stream

### void ost::AppLog::error (const char \* format, ...)

error level printf style method, provided for convenience.

**Parameters**

*format* printf format

### AppLog& ost::AppLog::error (void)` [inline]`

error level

**Returns**

application logger stream

### void ost::AppLog::identLevel (const char \* ident, Slog::Level level)

Sets the level for that ident.

**Parameters**

*ident* ident (module name for instance). \
 *level* level

### void ost::AppLog::info (const char \* format, ...)

info level printf style method, provided for convenience.

**Parameters**

*format* printf format

### AppLog& ost::AppLog::info (void)` [inline]`

info level

**Returns**

application logger stream

### void ost::AppLog::level (Slog::Level enable)

Sets the log level.

**Parameters**

*enable* log level.

### static Slog::Level ost::AppLog::levelTranslate (string name)` [inline]`, ` [static]`

Translates level from string to **Slog::Level**, useful for configuration files for instance. Valid level names are: 'emerg' for **Slog::levelEmergency** 'alert' for **Slog::levelAlert** 'critical' for **Slog::levelCritical** 'error' for **Slog::levelError** 'warn' for **Slog::levelWarning** 'notice' for **Slog::levelNotice** 'info' for **Slog::levelInfo** 'debug' for **Slog::levelDebug**

**Parameters**

*name* **Slog** Level name

**Returns**

**Slog** level value

### void ost::AppLog::logFileName (const char \* FileName, bool logDirectly = `false`, bool usePipe = `false`)

Allows to set up **ost::alog** parameters.

**Parameters**

*FileName* log file name. \
 *logDirectly* true to write directly to file, false to use a spooler like logger. \
 *usePipe* true to use pipe instead of file, false otherwise

### void ost::AppLog::notice (const char \* format, ...)

notice level printf style method, provided for convenience.

**Parameters**

*format* printf format

### AppLog& ost::AppLog::notice (void)` [inline]`

notice level

**Returns**

application logger stream

### void ost::AppLog::open (const char \* ident)

Opens the file if not already and sets ident.

**Parameters**

*ident* module name for instance.

### AppLog& ost::AppLog::operator() (const char \* ident, Slog::Level level = Slog::levelError)

operator to change ident and log level

**Parameters**

*ident* ident (module name for instance) \
 *level* new log level

**Returns**

application logger stream

### AppLog& ost::AppLog::operator() (Ident & ident)` [inline]`

operator to change ident

**Parameters**

*ident* ident (module name for instance)

**Returns**

application logger stream

References ost::AppLog::Ident::c\_str().

### AppLog& ost::AppLog::operator() (Slog::Level level)

operator to change logging level

**Parameters**

*level* new log level

**Returns**

application logger stream

### AppLog& ost::AppLog::operator\<\< (AppLog &(\*)(AppLog &) pfManipulator)

manipulator operator, to change print levels.

**Parameters**

*(\** pfManipulator)(**AppLog** &)

**Returns**

application logger stream

### AppLog& ost::AppLog::operator\<\< (Ident & ident)` [inline]`

operator \<\<

**Parameters**

*ident* module name for instance.

**Returns**

application logger stream

References ost::AppLog::Ident::c\_str().

### AppLog& ost::AppLog::operator\<\< (ostream &(\*)(ostream &) pfManipulator)

manipulator operator, to use ostream manipulators (i.e. std::endl,...)

**Parameters**

*(\** pfManipulator)(**AppLog** &)

**Returns**

application logger stream

### virtual int ost::AppLog::overflow (int c)` [virtual]`

stream **overflow()** overload.

**Parameters**

*c* character to be managed

**Returns**

c

### void ost::AppLog::slogEnable (bool en = `true`)

Enables slog output for error level messages.

**Parameters**

*en* true to enable slog output.

### void ost::AppLog::subscribe ()

Subscribes the current thread to logger, it reserves thread safe buffer for it.

### virtual int ost::AppLog::sync ()` [virtual]`

stream **sync()** overload

### void ost::AppLog::unsubscribe ()

Unsubscribes the current thread from logger.

### void ost::AppLog::warn (const char \* format, ...)

warn level printf style method, provided for convenience.

**Parameters**

*format* printf format

### AppLog& ost::AppLog::warn (void)` [inline]`

warn level

**Returns**

application logger stream

### void ost::AppLog::writeLog (bool endOfLine = `true`)` [protected]`

## Friends And Related Function Documentation

### ostream& operator\<\< (ostream & out, AppLog & al)` [friend]`

## Member Data Documentation

### map\<string, Slog::Level\>\* ost::AppLog::assoc` [static]`, ` [protected]`

### AppLogPrivate\* ost::AppLog::d` [protected]`

## Author

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