__pmspeclocalpmda(3) [centos man page]

PMSPECLOCALPMDA(3)					     Library Functions Manual						PMSPECLOCALPMDA(3)

NAME

       __pmSpecLocalPMDA - process command-line argument for the table of DSO PMDAs

C SYNOPSIS

       #include <pcp/pmapi.h>
       #include <pcp/impl.h>

       char *__pmSpecLocalPMDA(const char *spec);

       cc ... -lpcp

DESCRIPTION

       PCP  contexts  of  type	PM_CONTEXT_LOCAL  are used by clients that wish to fetch metrics directly from one or more PMDAs on the local host
       without involving pmcd(1).

       __pmSpecLocalPMDA provides a convenience wrapper to be used by applications that wish to use a command line argument (usually with  -K)	to
       control the DSO PMDAs that are available for a PM_CONTEXT_LOCAL context.

       The spec argument specifies actions for one or more DSO PMDAs using up to four fields separated by commas (``,''), namely:
       -  an opcode with one of the values add (add a new entry), del (delete an existing entry) or clear (clear all entries from the table).
       -  the PMDA's domain number
       -  the path to the PMDA DSO (may be absolute or relative to the $PCP_VAR_DIR/pmdas directory and the DSO suffix is optional), and
       -  the name of the PMDA's initialization routine.

       All  fields  are  required to add a new entry.  To delete an entry the opcode is required plus either or both of the domain number and path
       fields.	To clear all entries, only the opcode is required.

       If spec is parsed successfully, then __pmLocalPMDA(3) is called with the extracted arguments.

RETURN VALUE

       On success, __pmSpecLocalPMDA will return NULL.

       On error or failure, __pmSpecLocalPMDA will return a pointer to a static error message.

EXAMPLES

       Some examples of valid spec strings:

       clear  Delete all entries from the DSO table.

       add,123,foo/foo_pmda,foo_init
	      Add the ``foo'' PMDA using  domain  123.	 The  PMDA's  DSO  is  most  likely  in  below	the  directory	$PCP_PMDAS_DIR	and  named
	      foo/foo_pmda.so  (for ELF-style platforms) or foo/foo_pmda.dylib (for BSD-style platforms) or fooo_pmda.dll (for Windows-style plat-
	      forms).  The initialization routine for the ``foo'' PMDA is foo_init().

       del,123
	      Delete the entry for the DSO with domain 123.

       del,,foo/foo_pmda
	      Delete the entry with a pathname to the DSO that matches foo/foo_pmda.

       del,123,foo/foo_pmda
	      Delete the entry for the DSO with either domain 123 and/or a pathname to the DSO that matches foo/foo_pmda.

SEE ALSO

       PMAPI(3), __pmLocalPMDA(3) and pmNewContext(3).

Performance Co-Pilot														PMSPECLOCALPMDA(3)

PMLOCALPMDA(3)						     Library Functions Manual						    PMLOCALPMDA(3)

NAME

       __pmLocalPMDA - change the table of DSO PMDAs for PM_CONTEXT_LOCAL contexts

C SYNOPSIS

       #include <pcp/pmapi.h>
       #include <pcp/impl.h>

       int __pmLocalPMDA(int op, int domain, const char *name, const char *init);

       cc ... -lpcp

DESCRIPTION

       PCP  contexts  of  type	PM_CONTEXT_LOCAL  are used by clients that wish to fetch metrics directly from one or more PMDAs on the local host
       without involving pmcd(1).  A PMDA that is to be used in this way must have been built as a Dynamic Shared Object (DSO).

       Historically the table of PMDAs available for use with PM_CONTEXT_LOCAL was hardcoded to the following:

       * The PMDA (or PMDAs) that export the operating system performance data and data about process activity.
       * The mmv PMDA.
       * The sample PMDA provided $PCP_LITE_SAMPLE or $PMDA_LOCAL_SAMPLE is set in the environment - used mostly for QA and testing.

       The initial table of PMDAs available for use with PM_CONTEXT_LOCAL is now generated dynamically from all those PMDAs  that  have  been  in-
       stalled	as DSOs on the local host.  The one exception is the ``pmcd'' PMDA which only operates correctly in the address space of a running
       pmcd(1) process and so is not available to an application using a PM_CONTEXT_LOCAL context.

       __pmLocalPMDA provides a number of services to amend the table of PMDAs available for use with PM_CONTEXT_LOCAL.

       The op argument specifies the what should be done and takes one of the following values and actions:

       PM_LOCAL_ADD    Append an entry to the table for the PMDA with a Performance Metrics Domain (PMD) of domain, the path to the  DSO  PMDA	is
		       given by path and the PMDA's initialization routine is init.

       PM_LOCAL_DEL    Removes all entries in the table where the domain matches, or the path matches.	Setting the arguments domain to -1 or path
		       to NULL to force matching on the other argument.  The init argument is ignored.

       PM_LOCAL_CLEAR  Remove all entries from the table.  All the other arguments are ignored in this case.

       The domain, name and init arguments have similar syntax and semantics to the associated fields in the pmcd(1) configuration file.  The  one
       difference  is  the  path  argument  which  is  used  by  __pmLocalPMDA	to  find a likely looking DSO by searching in this order: $PCP_PM-
       DAS_DIR/path, path, $PCP_PMDAS_DIR/path.dso-suffix and finally path.dso-suffix (dso-suffix is the local platform specific default file name
       suffix for a DSO, e.g.  so for Linux, dylib for Mac OS X, dll for Windows, etc.).

RETURN VALUE

       In  most  cases,  __pmLocalPMDA	returns 0 to indicate success.	If op is invalid, then the return value is PM_ERR_CONV else if there is no
       matching table entry found for a PM_LOCAL_DEL operation, PM_ERR_INDOM is returned.

SEE ALSO

       pmcd(1), PMAPI(3), pmNewContext(3) and __pmSpecLocalPMDA(3).

Performance Co-Pilot														    PMLOCALPMDA(3)