PMUNITSSTR

Section: C Library Functions (3)
Index Return to Main Contents

NAME

pmUnitsStr , pmUnitsStr_r - convert a performance metric's units into a string

C SYNOPSIS

#include < pcp/pmapi.h >

const char *pmUnitsStr(const pmUnits * pu );
char *pmUnitsStr_r(const pmUnits * pu , char * buf , int buflen );

cc ... -lpcp

DESCRIPTION

The encoding of a performance metric's dimensionality and scale uses a pmUnits structure; see pmLookupDesc (3).

As an aid to labeling graphs and tables, or for error messages, pmUnitsStr will take a dimension and scale specification as per pu , and return the corresponding text string. The pmUnitsStr_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 60 bytes. If buflen is less than 60 then pmUnitsStr_r returns NULL and buf is not changed.

For example {1, -2, 0, PM_SPACE_MBYTE, PM_TIME_SEC, 0} , as the value of *pu gives the result string Mbyte / sec^2 .

The string value result from pmUnitsStr is held in a single static buffer, so the returned value is only valid until the next call to pmUnitsStr .

If the ``count'' dimension is non-zero, and the ``count'' scale is not zero, then the text string will include a decimal scaling factor, eg. count x 10^6 .

As a special case, if all components of the dimension are zero, then the ``count'' scale is used to produce the text. If this scale is zero the result is an empty string, otherwise the result is of the form x1 0^2 .

NOTES

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

SEE ALSO

PMAPI (3), pmAtomStr (3), pmConvScale (3), pmExtractValue (3), pmLookupDesc (3), pmPrintValue (3), pmIDStr (3), pmInDomStr (3), pmTypeStr (3), pmSemStr (3) and pmUnitsStr (3).


Index

NAME
C SYNOPSIS
DESCRIPTION
NOTES
SEE ALSO