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 , ECGEOF = 50023 , ECGCONFIGPARSEFAIL ,   ECGNAMESPACEPATHS , ECGNAMESPACECONTROLLER , ECGMOUNTNAMESPACE , ECGROUPUNSUPP ,   ECGCANTSETVALUE , ECGNONEMPTY , ECGNOVERSIONCONVERT }
const char *	cgroup_strerror (int code)
int	cgroup_get_last_errno (void)
#define	ECGRULESPARSEFAIL   ECGROUPPARSEFAIL

Detailed Description

Macro Definition Documentation

ECGRULESPARSEFAIL

#define ECGRULESPARSEFAIL   ECGROUPPARSEFAIL

Legacy definition of ECGRULESPARSEFAIL error code.

Enumeration Type Documentation

anonymous enum

anonymous enum

Enumerator
ECGROUPMULTIMOUNTED	Controllers bound to different mount points
ECGOTHER	Represents error coming from other libraries like glibc. libcgroup users need to check cgroup_get_last_errno() upon encountering this error.
ECGROUPPARSEFAIL	Failed to parse rules configuration file.
ECGROUPNORULES	Rules list does not exist.
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).
ECGNONEMPTY	Removing of a group failed because it was not empty.
ECGNOVERSIONCONVERT	Failed to convert from cgroup v1 to/from cgroup v2

Function Documentation

cgroup_get_last_errno()

int cgroup_get_last_errno

(

void

)

Return last errno, which caused ECGOTHER error.

cgroup_strerror()

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.