pmparsehostspec(3) — Linux manual page

NAME | C SYNOPSIS | CAVEAT | DESCRIPTION | RETURN VALUE | SEE ALSO | COLOPHON

PMPARSEHOSTSPEC(3)      Library Functions Manual      PMPARSEHOSTSPEC(3)

NAME         top

       __pmParseHostSpec, __pmUnparseHostSpec, __pmFreeHostSpec -
       uniform host specification parser

C SYNOPSIS         top

       #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

CAVEAT         top

       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.

DESCRIPTION         top

       __pmParseHostSpec  accepts  a string specifying the location of a
       PCP performance metric collector daemon.  The syntax of the vari‐
       ous formats of this string is described in PCPIntro(1) where sev‐
       eral 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 list of  port  numbers
       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  speci‐
       fied (currently, only one proxy host is supported by the PCP pro‐
       tocols).   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 repre‐
       sent 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.

RETURN VALUE         top

       If the given string is successfully parsed __pmParseHostSpec  re‐
       turns  zero.  In this case the dynamic storage allocated by __pm‐
       ParseHostSpec can be released by calling  __pmFreeHostSpec  using
       the address returned from __pmParseHostSpec via hosts.

       __pmParseHostSpec  returns PM_ERR_GENERIC and a dynamically allo‐
       cated 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 suc‐
       cess, errmsg is undefined.

       On success __pmUnparseHostSpec returns a positive value  indicat‐
       ing  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.

SEE ALSO         top

       pmcd(1),   pmproxy(1),   pmchart(1),   __pmParseHostAttrsSpec(3),
       PMAPI(3) and pmNewContext(3).

COLOPHON         top

       This page is part of the PCP (Performance Co-Pilot) project.  In‐
       formation about the project can be found at ⟨http://www.pcp.io/⟩.
       If you have a bug  report  for  this  manual  page,  send  it  to
       [email protected].    This  page  was  obtained  from  the  project's
       upstream                      Git                      repository
       ⟨https://github.com/performancecopilot/pcp.git⟩   on  2024-06-14.
       (At that time, the date of the most recent commit that was  found
       in the repository was 2024-06-14.)  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
       [email protected]

Performance Co-Pilot               PCP                PMPARSEHOSTSPEC(3)

Pages that refer to this page: pmparsehostattrsspec(3)