6. Error handling

Error handling
Unless states otherwise in documentation of a function, all functions return `int`, which is zero (0) when the function succeeds, and positive number if the function fails. The returned integer is one of the ECG* values described below. Value ECGOTHER means that the error was caused by underlying OS and the real cause can be found by calling cgroup_get_last_errno().
enum	{ ECGROUPNOTCOMPILED = 50000, ECGROUPNOTMOUNTED, ECGROUPNOTEXIST, ECGROUPNOTCREATED, ECGROUPSUBSYSNOTMOUNTED, ECGROUPNOTOWNER, ECGROUPMULTIMOUNTED, ECGROUPNOTALLOWED, ECGMAXVALUESEXCEEDED, ECGCONTROLLEREXISTS, ECGVALUEEXISTS, ECGINVAL, ECGCONTROLLERCREATEFAILED, ECGFAIL, ECGROUPNOTINITIALIZED, ECGROUPVALUENOTEXIST, ECGOTHER, ECGROUPNOTEQUAL, ECGCONTROLLERNOTEQUAL, ECGROUPPARSEFAIL, ECGROUPNORULES, ECGMOUNTFAIL, ECGSENTINEL, ECGEOF, ECGCONFIGPARSEFAIL, ECGNAMESPACEPATHS, ECGNAMESPACECONTROLLER, ECGMOUNTNAMESPACE }
const char *	cgroup_strerror (int code)
	Format error code to a human-readable English string.
int	cgroup_get_last_errno (void)
	Return last errno, which caused ECGOTHER error.
#define	ECGRULESPARSEFAIL ECGROUPPARSEFAIL
	Legacy definition of ECGRULESPARSEFAIL error code.

Define Documentation

#define ECGRULESPARSEFAIL ECGROUPPARSEFAIL

Legacy definition of ECGRULESPARSEFAIL error code.

Enumeration Type Documentation

anonymous enum

Enumerator:

ECGROUPNOTCOMPILED
ECGROUPNOTMOUNTED
ECGROUPNOTEXIST
ECGROUPNOTCREATED
ECGROUPSUBSYSNOTMOUNTED
ECGROUPNOTOWNER
ECGROUPMULTIMOUNTED	Controllers bound to different mount points.
ECGROUPNOTALLOWED
ECGMAXVALUESEXCEEDED
ECGCONTROLLEREXISTS
ECGVALUEEXISTS
ECGINVAL
ECGCONTROLLERCREATEFAILED
ECGFAIL
ECGROUPNOTINITIALIZED
ECGROUPVALUENOTEXIST
ECGOTHER	Represents error coming from other libraries like glibc. `libcgroup` users need to check cgroup_get_last_errno() upon encountering this error.
ECGROUPNOTEQUAL
ECGCONTROLLERNOTEQUAL
ECGROUPPARSEFAIL	Failed to parse rules configuration file.
ECGROUPNORULES	Rules list does not exist.
ECGMOUNTFAIL
ECGSENTINEL	Not an real error, just a auxiliary mark in the enum. Please insert further error codes above this.
ECGEOF	Not an real error, it just indicates that iterator has come to end of sequence and no more items are left.
ECGCONFIGPARSEFAIL	Failed to parse config file (cgconfig.conf).
ECGNAMESPACEPATHS
ECGNAMESPACECONTROLLER
ECGMOUNTNAMESPACE

Function Documentation

int cgroup_get_last_errno ( void )

Return last errno, which caused ECGOTHER error.

const char* cgroup_strerror ( int code )

Format error code to a human-readable English string.

No internationalization is currently done. Returned pointer leads to libcgroup memory and must not be freed nor modified. The memory is rewritten by subsequent call to this function.

Parameters:

code

Error code for which the corresponding error string is returned. When ECGOTHER is used, text with glibc's description of cgroup_get_last_errno() value is returned.