[R] require() is not giving TRUE / FALSE statements ?

[Wolfgang Raffelsberger]

Dear list,

?require says :
"... |require| is designed for use inside other functions; it returns 
|FALSE| and gives a warning (rather than an error as |library()| does by 
default) if the package does not exist ..."

However when I run the following code I don't get any TRUE / FALSE 
statements (but the warning only).
Since I want to test from inside of a function if a given package is 
installed (and do some specific actions like eg trying to install if the 
answer is negative), I need the FALSE statement for use with if(). I 
found a work-around (see below), but I wanted to bring to your attention 
that require() doesn't give the message(s) it's supposed to return.

Wolfgang

 > require(stats)
 > require(doesNotExist)        # example for library that's not 
existing on my system
Loading required package: doesNotExist
Warning message:
In library(package, lib.loc = lib.loc, character.only = TRUE, 
logical.return = TRUE,  :
  there is no package called 'doesNotExist'

 >## After all I found a work-around with :
 >library(doesNotExist,logical.return=T)
[1] FALSE
Warning message:
In library(doesNotExist, logical.return = T) :
  there is no package called 'doesNotExist'


 >## for completeness :
 > sessionInfo()
R version 2.8.1 (2008-12-22)
i386-pc-mingw32

locale:
LC_COLLATE=French_France.1252;LC_CTYPE=French_France.1252;LC_MONETARY=French_France.1252;LC_NUMERIC=C;LC_TIME=French_France.1252

attached base packages:
[1] stats     graphics  grDevices datasets  tcltk     utils     
methods   base    

other attached packages:
[1] RODBC_1.2-4    svSocket_0.9-5 svIO_0.9-5     R2HTML_1.59    
svMisc_0.9-5   svIDE_0.9-5  

loaded via a namespace (and not attached):
[1] tools_2.8.1


 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wolfgang Raffelsberger, PhD
Laboratoire de BioInformatique et Génomique Intégratives
CNRS UMR7104, IGBMC 
1 rue Laurent Fries,  67404 Illkirch  Strasbourg,  France
Tel (+33) 388 65 3300         Fax (+33) 388 65 3276
wolfgang.raffelsberger (at) igbmc.fr