pmnumberstr(3) — Linux manual page

NAME | C SYNOPSIS | DESCRIPTION | NOTES | SEE ALSO | COLOPHON

PMNUMBERSTR(3)           Library Functions Manual          PMNUMBERSTR(3)

NAME         top

       pmNumberStr, pmNumberStr_r - fixed width output format for numbers

C SYNOPSIS         top

       #include <pcp/pmapi.h>

       const char *pmNumberStr(double value);
       char *pmNumberStr_r(double value, char *buf, int buflen);

       cc ... -lpcp

DESCRIPTION         top

       pmNumberStr  returns  the  address of a 8-byte buffer that holds a
       null-byte terminated representation of value suitable  for  output
       with  fixed  width  fields.   The  pmNumberStr_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 8 bytes.

       The  value  is  scaled  using multipliers in powers of ``one thou‐
       sand'' (the decimal ``kilo'') and has a bias that provides greater
       precision for positive numbers as opposed to negative numbers.

       The format depends on the sign and magnitude of value  as  follows
       (d represents a decimal digit):
                ┌───────────────────────────────────┬─────────┐
                │            value range            │ format  │
                ├───────────────────────────────────┼─────────┤
                │         > 999995000000000         │  inf?   │
                │ 999995000000000 - 999995000000    │ ddd.ddT │
                │    999995000000 - 999995000       │ ddd.ddG │
                │       999995000 - 999995          │ ddd.ddM │
                │          999995 - 999.995         │ ddd.ddK │
                │         999.995 - 0.005           │ ddd.dd  │
                │           0.005 - -0.005          │   0.00  │
                │          -0.005 - -99.95          │ -dd.dd  │
                │         -99.995 - -99995          │ -dd.ddK │
                │          -99995 - -99995000       │ -dd.ddM │
                │       -99995000 - -99995000000    │ -dd.ddG │
                │    -99995000000 - -99995000000000 │ -dd.ddT │
                │        < -99995000000000          │ -inf?   │
                └───────────────────────────────────┴─────────┘

       At  the  boundary points of the ranges, the chosen format will re‐
       tain the maximum number of significant digits.

NOTES         top

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

SEE ALSO         top

       printf(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/⟩.
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       pcp@groups.io.  This page was obtained from the project's upstream
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Performance Co-Pilot               PCP                     PMNUMBERSTR(3)