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NAME | C SYNOPSIS | CAVEAT | DESCRIPTION | RETURN VALUE | SEE ALSO | COLOPHON |
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PMPARSEHOSTSPEC(3) Library Functions Manual PMPARSEHOSTSPEC(3)
__pmParseHostSpec, __pmUnparseHostSpec, __pmFreeHostSpec - uniform
host specification parser
#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
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.
__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.
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.
pmcd(1), pmproxy(1), pmchart(1), __pmParseHostAttrsSpec(3), PMAPI(3)
and pmNewContext(3).
This page is part of the PCP (Performance Co-Pilot) project.
Information about the project can be found at ⟨http://www.pcp.io/⟩.
If you have a bug report for this manual page, send it to
pcp@groups.io. This page was obtained from the project's upstream
Git repository ⟨https://github.com/performancecopilot/pcp.git⟩ on
2018-02-02. (At that time, the date of the most recent commit that
was found in the repository was 2018-02-02.) If you discover any
rendering problems in this HTML version of the page, or you believe
there is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
Performance Co-Pilot PCP PMPARSEHOSTSPEC(3)
Pages that refer to this page: pmparsehostattrsspec(3)
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