pmIDStr_r(3) convert a performance metric identifier into a string

Other Alias



#include <pcp/pmapi.h>

const char *pmIDStr(pmID pmid);
char *pmIDStr_r(pmID pmid, char *buf, int buflen);

cc ... -lpcp


For use in error and diagnostic messages, pmIDStr returns a `human readable' version of the specified Performance Metric Identifier (PMID). The pmIDStr_r function does the same, but stores the result in a user-supplied buffer buf of length buflen, which should have room for at least 20 bytes.

Internally, a PMID is encoded as follows;

typedef struct {
    int             pad:2;
    unsigned int    domain:8;
    unsigned int    cluster:12;
    unsigned int    item:10;
} __pmID_int;

pmIDStr returns a string with each of the domain, cluster and item subfields appearing as decimal numbers, separated by periods.

The string value result from pmIDStr is held in a single static buffer, so the returned value is only valid until the next call to pmIDStr.


pmIDStr returns a pointer to a static buffer and hence is not thread-safe. Multi-threaded applications should use pmIDStr_r instead.


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 configuration file, as described in pcp.conf(5). Values for these variables may be obtained programmatically using the pmGetConfig(3) function.