pmgetarchivelabel(3) [centos man page]

PMGETARCHIVELABEL(3)					     Library Functions Manual					      PMGETARCHIVELABEL(3)

NAME

       pmGetArchiveLabel - fetch the label record from a performance metrics archive log

C SYNOPSIS

       #include <pcp/pmapi.h>

       int pmGetArchiveLabel(pmLogLabel *lp);

       cc ... -lpcp

DESCRIPTION

       Within  the  framework of the Performance Co-Pilot (PCP), archive logs of performance metrics values may be accumulated and saved using the
       program pmlogger(1).

       The routine pmGetArchiveLabel may be used to fetch the label record from an archive log that has already been opened using pmNewContext(3),
       or pmDupContext(3), and thereby associated with the current Performance Metrics Application Programming Interface (PMAPI) context.

       The  result  returned  via  the pointer lp is a structure that must be pre-allocated by the caller and has the following format (defined in
       pmapi.h).

	 /*
	  * Label Record at the start of every log file
	  */
	 typedef struct {
	   int	      ll_magic;    /* PM_LOG_MAGIC | log format version no. */
	   pid_t      ll_pid;	   /* PID of logger */
	   struct timeval ll_start;/* start of this log */
	   char       ll_hostname[PM_LOG_MAXHOSTLEN]; /* name of collection host */
	   char       ll_tz[40];   /* $TZ at collection host */
	 } pmLogLabel;

       For an application, the most useful information from the archive label is likely to be in the fields ll_start, ll_hostname or ll_tz.

       Note that the size of the ll_hostname field is PM_LOG_MAXHOSTLEN (64 bytes) which is less than  MAXHOSTNAMELEN  (see  gethostbyname(3))	on
       some platforms.	These semantics are necessary to retain backwards compatibility with the PCP archive file format.

       pmGetArchiveLabel returns zero for success.

PCP ENVIRONMENT

       Environment  variables  with  the prefix PCP_ are used to parameterize the file and directory names used by PCP.  On each installation, the
       file /etc/pcp.conf contains the local values for these variables.  The $PCP_CONF variable may be used to specify an alternative	configura-
       tion file, as described in pcp.conf(5).	Values for these variables may be obtained programmatically using the pmGetConfig(3) function.

SEE ALSO

       pmlogger(1), PMAPI(3), pmDupContext(3), pmGetConfig(3), pmNewContext(3), pcp.conf(5) and pcp.env(5).

DIAGNOSTICS

       PM_ERR_NOCONTEXT
	      the current PMAPI context is either invalid, or not associated with an archive log

Performance Co-Pilot							PCP						      PMGETARCHIVELABEL(3)

PMGETCONFIG(3)						     Library Functions Manual						    PMGETCONFIG(3)

NAME

       pmGetConfig - return Performance Co-Pilot configuration variable

C SYNOPSIS

       #include <pcp/pmapi.h>
       char *pmGetConfig(const char *variable);

       #include <pcp/impl.h>
       char *__pmGetAPIConfig(const char *feature);

       cc ... -lpcp

DESCRIPTION

       The  pmGetConfig function searches for variable first in the environment and then, if not found, in the Performance Co-Pilot (PCP) configu-
       ration file and returns the string result.  If variable is not already in the environment, it is added with  a  call  to  putenv(3)  before
       returning.

       The default location of the PCP configuration file is /etc/pcp.conf but this may be changed by setting PCP_CONF in the environment to a new
       location, as described in pcp.conf(5).

       The internal __pmGetAPIConfig function reports on features of the PCP library.  It can be used to query support for multi-threading,  secu-
       rity extensions, and other features.

       The  pmconfig(1)  utility provides command line access to both of these interfaces, and also provides a mechanism for listing all available
       variables and features that are valid arguments to these routines.

RETURN VALUE

       If variable is not found in either the environment nor the PCP configuration file then the return value is an empty  string.   If  the  PCP
       configuration  file  is	not found then a fatal error message is printed and the process will exit(2) - although this sounds drastic, it is
       the only course of action available because the PCP configuration/installation is fatally flawed.

       If the pmGetConfig function returns a non-empty string, the returned value points into the environment and so changing it is  a	bad  idea.
       This function returns the same type as the getenv(3) function (which should probably be a const char *).

       The  __pmGetAPIConfig  routine  on the other hand returns NULL on failure to lookup the requested feature.  It does not modify the environ-
       ment, and returns a pointer to a static read-only string which also should not be modified or freed by the caller.

PCP ENVIRONMENT

       Environment variables with the prefix PCP_ are used to parameterize the file and directory names used by PCP.  On  each	installation,  the
       file  /etc/pcp.conf contains the local values for these variables.  The $PCP_CONF variable may be used to specify an alternative configura-
       tion file, as described in pcp.conf(5).	Values for these variables may be obtained programmatically using the pmGetConfig(3) function.

SEE ALSO

       PCPIntro(1), pmconfig(1), exit(2), PMAPI(3), getenv(3C), putenv(3C), pcp.conf(5), pcp.env(5) and environ(5).

Performance Co-Pilot							PCP							    PMGETCONFIG(3)