---
name: "pmGetHighResArchiveLabel"
section: "3"
platform: "linux"
package: "libpcp3-dev"
version: "6.3.8-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/pmGetArchiveLabel"
---

# pmGetHighResArchiveLabel(3)

fetch the label record from a set of performance metrics archives

Part of [pmGetArchiveLabel(3)](/pmGetArchiveLabel/3.md).

## NAME

**pmGetArchiveLabel**, **pmGetHighResArchiveLabel** - fetch the label record from a set of performance metrics archives

## C SYNOPSIS

**#include \<pcp/pmapi.h\>**

```
int pmGetArchiveLabel(pmLogLabel *lp);
int pmGetHighResArchiveLabel(pmHighResLogLabel *lp);
```

**cc ... -lpcp**

## DESCRIPTION

Within the framework of the Performance Co-Pilot (PCP), archives of performance metrics values may be accumulated and saved using the program [**pmlogger**(1)](/pmlogger/1.md) and the [**LOGIMPORT**(3)](/LOGIMPORT/3.md) programming interface.

The routines **pmGetArchiveLabel** and **pmGetHighResArchiveLabel** may be used to fetch the label record from a set of archives that has already been opened using [**pmNewContext**(3)](/pmNewContext/3.md), or [**pmDupContext**(3)](/pmDupContext/3.md), and thereby associated with the current Performance Metrics Application Programming Interface (PMAPI) context.

It is recommended that new applications use the high resolution API and existing applications transition to this interface over time.

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

```
typedef struct {
  int        magic;       /* PM_LOG_MAGIC | archive format version no. */
  pid_t      pid;         /* PID of logger */
  struct timespec start;  /* start of this archive */
  char       hostname[PM_MAX_HOSTNAMELEN];   /* collection host full name */
  char       timezone[PM_MAX_TIMEZONELEN];   /* generic, squashed $TZ */
  char       zoneinfo[PM_MAX_ZONEINFOLEN];   /* local platform $TZ */
} pmHighResLogLabel;
typedef struct {
  int        ll_magic;    /* PM_LOG_MAGIC | archive format version no. */
  pid_t      ll_pid;      /* PID of logger */
  struct timeval ll_start;/* start of this archive */
  char       ll_hostname[PM_LOG_MAXHOSTLEN]; /* name of collection host */
  char       ll_tz[40];   /* $TZ at collection host */
} pmLogLabel;
```

Both forms can be used with either version 2 or version 3 archives. However, the pmHighResLogLabel structure provides the higher resolution start time stored in the newer format, as well as the full timezone and extended length host name fields. For detailed information about the archive on-disk format, refer to [**LOGARCHIVE**(5)](/LOGARCHIVE/5.md).

For an application using **pmGetHighResArchiveLabel**, the most useful information from the archive label is likely to be in the fields *start*, *hostname*, *timezone*, and *zoneinfo*.

The *zoneinfo* field contains the most detailed timezone information available, and should be used if present (non-zero length string). It will only not be present in the case of version 2 archives - this is a new field added as part of the version 3 format. The *timezone* field will always be present, however it is the 'squashed' timezone value and in certain situations is not the most accurate timezone.

For older applications using **pmGetArchiveLabel**, 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)](/gethostbyname/3.md)) on some platforms. These semantics are necessary to retain backwards compatibility with the PCP archive file format.

Both **pmGetArchiveLabel** and **pmGetHighResArchiveLabel** return zero for success.

## DIAGNOSTICS

- **PM\_ERR\_NOCONTEXT**

  the current PMAPI context is either invalid, or not associated with a set of archives

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

## SEE ALSO

[**pmlogger**(1)](/pmlogger/1.md), [**LOGIMPORT**(3)](/LOGIMPORT/3.md), [**PMAPI**(3)](/PMAPI/3.md), [**pmDupContext**(3)](/pmDupContext/3.md), [**pmGetConfig**(3)](/pmGetConfig/3.md), [**pmNewContext**(3)](/pmNewContext/3.md), [**LOGARCHIVE**(5)](/LOGARCHIVE/5.md), [**pcp.conf**(5)](/pcp.conf/5.md) and [**pcp.env**(5)](/pcp.env/5.md).