返回R中成功或失败的write.table的代码

Question

问题：有没有办法可以返回成功或失败write.table来电的结果？这就是我试过的：

> x <- write.table(mydata, file="AllDat.csv", sep=",", row.names = FALSE, col.names=TRUE, append=FALSE

Error in file(file, ifelse(append, "a", "w")) :cannot open the connection
In addition: Warning message: In file(file, ifelse(append, "a", "w")) : cannot open file 'AllDat.csv': Permission denied

> x
NULL

即使成功write.table，变量x仍为NULL。