picotm-libc.h File Reference

Public interfaces of picotm's libc module. More...

#include <picotm/compiler.h>
#include <picotm/config/picotm-libc-config.h>

Enumerations
enum	picotm_libc_cc_mode { PICOTM_LIBC_CC_MODE_NOUNDO, PICOTM_LIBC_CC_MODE_2PL }
enum	picotm_libc_error_recovery { PICOTM_LIBC_ERROR_RECOVERY_AUTO, PICOTM_LIBC_ERROR_RECOVERY_FULL }
enum	picotm_libc_file_type {   PICOTM_LIBC_FILE_TYPE_CHRDEV, PICOTM_LIBC_FILE_TYPE_FIFO, PICOTM_LIBC_FILE_TYPE_REGULAR, PICOTM_LIBC_FILE_TYPE_DIR,   PICOTM_LIBC_FILE_TYPE_SOCKET }
enum	picotm_libc_write_mode { PICOTM_LIBC_WRITE_BACK, PICOTM_LIBC_WRITE_THROUGH }

Functions
PICOTM_NOTHROW enum picotm_libc_error_recovery	picotm_libc_get_error_recovery (void)
PICOTM_NOTHROW enum picotm_libc_cc_mode	picotm_libc_get_file_type_cc_mode (enum picotm_libc_file_type file_type)
PICOTM_NOTHROW void	picotm_libc_save_errno (void)
PICOTM_NOTHROW void	picotm_libc_set_error_recovery (enum picotm_libc_error_recovery recovery)
PICOTM_NOTHROW void	picotm_libc_set_file_type_cc_mode (enum picotm_libc_file_type file_type, enum picotm_libc_cc_mode cc_mode)

Enumeration Type Documentation

picotm_libc_cc_mode

enum picotm_libc_cc_mode

Concurrency-control mode for file-descriptor I/O.

Enumerator
PICOTM_LIBC_CC_MODE_NOUNDO	Set CC mode to irrevocablilty
PICOTM_LIBC_CC_MODE_2PL	Set CC mode to pessimistic two-phase locking

picotm_libc_error_recovery

enum picotm_libc_error_recovery

The error-recovery strategy for system calls.

Each module detects errors and initiates recovery. Sometimes reported errors are not failures of the component, but expected corner cases. For example 'read()' on non-blocking file descriptors signals EAGAIN if there's no data available.

The libc modules has to distiguish such cases from actual errors to decide when to initiate recovery. enum picotm_libc_error_recovery is a list of possible strategies.

It is recommended to use PICOTM_LIBC_ERROR_RECOVERY_AUTO.

Enumerator
PICOTM_LIBC_ERROR_RECOVERY_AUTO	Use heuristics to decide which errors to recover from. This is the default.
PICOTM_LIBC_ERROR_RECOVERY_FULL	Recover from all errors.

picotm_libc_file_type

enum picotm_libc_file_type

File-type constants.

Enumerator
PICOTM_LIBC_FILE_TYPE_CHRDEV	Character device.
PICOTM_LIBC_FILE_TYPE_FIFO	FIFO.
PICOTM_LIBC_FILE_TYPE_REGULAR	Regular file.
PICOTM_LIBC_FILE_TYPE_DIR	Directory.
PICOTM_LIBC_FILE_TYPE_SOCKET	Socket.

picotm_libc_write_mode

enum picotm_libc_write_mode

File-descriptor I/O write mode.

Enumerator
PICOTM_LIBC_WRITE_BACK	Write-back mode.
PICOTM_LIBC_WRITE_THROUGH	Write-through mode.

Function Documentation

picotm_libc_get_error_recovery()

PICOTM_NOTHROW enum picotm_libc_error_recovery picotm_libc_get_error_recovery

(

void

)

Returns the strategy for deciding when to recover from errors.

Returns

The current error-recovering strategy.

picotm_libc_get_file_type_cc_mode()

PICOTM_NOTHROW enum picotm_libc_cc_mode picotm_libc_get_file_type_cc_mode

(

enum picotm_libc_file_type

file_type

)

Returns the currently preferred mode of concurrency control for I/O on a specific file type.

Parameters

file_type

The file type to get the CC mode from.

Returns

The current CC mode for the given file type.

picotm_libc_save_errno()

PICOTM_NOTHROW void picotm_libc_save_errno

(

void

)

Saves the value of 'errno' during a transaction. Module authors should call this function before invoking a function that might modify errno's value.

picotm_libc_set_error_recovery()

PICOTM_NOTHROW void picotm_libc_set_error_recovery

(

enum picotm_libc_error_recovery

recovery

)

Sets the strategy for deciding when to recover from errors.

Parameters

recovery

The error-recovering strategy.

picotm_libc_set_file_type_cc_mode()

PICOTM_NOTHROW void picotm_libc_set_file_type_cc_mode	(	enum picotm_libc_file_type	file_type,
		enum picotm_libc_cc_mode	cc_mode
	)

Sets the preferred mode of concurrency control for I/O on a specific file type.

Parameters

file_type	The file type to set the CC mode for.
cc_mode	The CC mode.