единый синтаксический анализатор спецификации хоста (uniform host specification parser)
Имя (Name)
__pmParseHostSpec, __pmUnparseHostSpec, __pmFreeHostSpec -
uniform host specification parser
Синопсис C (C Synopsis)
#include "pmapi.h"
#include "libpcp.h"
int __pmParseHostSpec(const char *string, pmHostSpec **hostsp,
int *count, char **errmsg);
int __pmUnparseHostSpec(pmHostSpec *hosts, int count, char
*string, size_t size);
void __pmFreeHostSpec(pmHostSpec *hosts, int count);
cc ... -lpcp
Предостережение (Caveat)
This documentation is intended for internal Performance Co-Pilot
(PCP) developer use.
These interfaces are not part of the PCP APIs that are guaranteed
to remain fixed across releases, and they may not work, or may
provide different semantics at some point in the future.
Описание (Description)
__pmParseHostSpec accepts a string specifying the location of a
PCP performance metric collector daemon. The syntax of the
various formats of this string is described in PCPIntro(1) where
several examples are also presented.
The syntax allows the initial pmcd(1) hostname to be optionally
followed by a list of port numbers, which will be tried in order
when connecting to pmcd on that host. The portlist is separated
from the hostname using a colon, and each port in the list is
comma-separated.
In addition, one or more optional pmproxy(1) hosts can be
specified (currently, only one proxy host is supported by the PCP
protocols). These are separated from each other and from the
pmcd component using the @ character. These may also be followed
by an optional port list, using the same comma-separated syntax
as before.
__pmParseHostSpec takes a null-terminated host specification
string and returns an array of pmHostSpec structures, where the
array has count entries.
These pmHostSpec structures that are returned via hostsp
represent each individual host in the specification string and
has the following declaration:
typedef struct {
char *name; /* hostname (always valid) */
int *ports; /* array of host port numbers */
int nports; /* number of ports in host port array */
} pmHostSpec;
__pmUnparseHostSpec performs the inverse operation, creating a
string representation from a number of hosts structures. Where
the count of structures indicated by hosts is greater than one,
the proxy syntax is used to indicate a chain of proxied hosts.
The size of the supplied string buffer must be provided by the
caller using the size parameter.
Возвращаемое значение (Return value)
If the given string is successfully parsed __pmParseHostSpec
returns zero. In this case the dynamic storage allocated by
__pmParseHostSpec can be released by calling __pmFreeHostSpec
using the address returned from __pmParseHostSpec via hosts.
__pmParseHostSpec returns PM_ERR_GENERIC and a dynamically
allocated error message string in errmsg, if the given string
does not parse, and the user-supplied errmsg pointer is non-null.
Be sure to free(3) the error message string in this situation.
In the case of an error, hosts is undefined. In the case of
success, errmsg is undefined.
On success __pmUnparseHostSpec returns a positive value
indicating the number of characters written into the supplied
buffer. However, if the supplied buffer was too small, a
negative status code of -E2BIG is returned.
Смотри также (See also)
pmcd(1), pmproxy(1), pmchart(1), __pmParseHostAttrsSpec(3),
PMAPI(3) and pmNewContext(3).
